Ginkgo leaf • Astragalus • Flowery Knotweed (he shou wu) • Schizandra berry • Red Peony • Tender Green Tea leaf • Jasmine flower.
Brand name products often contain multiple ingredients. To read detailed information about each ingredient, click on the link for the individual ingredient shown above.
Below is general information about the effectiveness of the known ingredients contained in the product Ginkgo Biloba Herb Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
Below is general information about the safety of the known ingredients contained in the product Ginkgo Biloba Herb Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
POSSIBLY SAFE ...when used orally and appropriately. Doses of astragalus up to 60 grams daily for up to 4 months have been used without reported adverse effects (32920,33038,95909,114804). ...when used intravenously. Infusion of doses up to 80 grams daily for up to 4 months under the supervision of a medical professional have been used with apparent safety (32811,32812,32828,95909,114688,114804). There is insufficient reliable information available about the safety of astragalus when used topically.
PREGNANCY AND LACTATION:
There is insufficient reliable information in humans.
However, astragaloside, a constituent of astragalus, has maternal and fetal toxic effects in animals (32881). Avoid using.
LIKELY SAFE ...when used orally and appropriately. Standardized ginkgo leaf extracts have been used safely in trials lasting for several weeks up to 6 years (1514,1515,3461,5717,5718,6211,6212,6213,6214,6215)(6216,6222,6223,6224,6225,6490,14383,14499,16634,16635)(16636,16637,17402,17716,17718,87794,87819,87826,87848,87864)(87888,87897,87901,87904,89701,89707,107359,107360). There have been some reports of arrhythmias associated with ginkgo leaf extract. However, it is not yet clear if ginkgo might cause arrhythmia (105253,105254). There is some concern about toxic and carcinogenic effects seen in animals exposed to a ginkgo leaf extract containing 31.2% flavonoids, 15.4% terpenoids, and 10.45 ppm ginkgolic acid, in doses of 100 to 2000 mg/kg five times per week for 2 years (18272). However, the clinical relevance of this data for humans, using typical doses, is unclear. The content of the extract used is not identical to that commonly used in supplement products, and the doses studied are much higher than those typically used by humans. A single dose of 50 mg/kg in rats is estimated to be equivalent to a single dose of about 240 mg in humans (18272).
POSSIBLY SAFE ...when used intravenously, short-term. A standardized ginkgo leaf extract called EGb 761 ONC has been safely administered intravenously for up to 14 days (9871,9872,107360,107452). A Chinese preparation containing ginkgo leaf extract and dipyridamole has been safely administered intravenously for up to 30 days (102881,102882). ...when applied topically, short-term. There was no dermal irritation during a 24-hour patch test using the leaf extract, and no sensitization with repeat applications (112946). When used topically in cosmetics, extracts of ginkgo leaves are reported to be safe, but there is insufficient data to determine the safety of nut and root extracts, and isolated biflavones and terpenoids (112946).
POSSIBLY UNSAFE ...when the roasted seed or crude ginkgo plant is used orally. Consuming more than 10 roasted seeds per day can cause difficulty breathing, weak pulse, seizures, loss of consciousness, and shock (8231,8232). Crude ginkgo plant parts can exceed concentrations of 5 ppm of the toxic ginkgolic acid constituents and can cause severe allergic reactions (5714).
LIKELY UNSAFE ...when the fresh ginkgo seed is used orally. Fresh seeds are toxic and potentially deadly (11296).
PREGNANCY: POSSIBLY UNSAFE
when used orally.
There is concern that ginkgo might have labor-inducing and hormonal effects. There is also concern that the antiplatelet effects of ginkgo could prolong bleeding time if taken around the time of labor and delivery (15052). Theoretically, ginkgo might adversely affect pregnancy outcome; avoid using during pregnancy.
LACTATION:
Insufficient reliable information available; avoid using.
CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term (87790,89708).
A specific ginkgo dried extract (Ginko T.D., Tolidaru Pharmaceuticals), has been safely used in doses of 80-120 mg daily for 6 weeks in children aged 6-14 years (17112,95669). Another specific combination product containing ginkgo leaf extract and American ginseng extract (AD-FX, CV Technologies, Canada) has also been safely used in children aged 3-17 years for up to 4 weeks (8235).
CHILDREN: LIKELY UNSAFE
when ginkgo seed is used orally.
The fresh seeds have caused seizures and death in children (8231,11296).
LIKELY SAFE ...when green tea is consumed as a beverage in moderate amounts (733,6031,9222,9223,9225,9226,9227,9228,14136,90156)(90159,90168,90174,90184,95696). Green tea contains caffeine. According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, drinking up to 8 cups of green tea daily, or approximately 400 mg of caffeine, is not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806). ...when a specific green tea extract ointment is used topically and appropriately, short-term. The specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins is an FDA-approved prescription product. It has been safely used in trials lasting up to 16 weeks (15067). The safety of treatment beyond 16 weeks or multiple treatment courses is not known.
POSSIBLY SAFE ...when green tea extract is used orally. Green tea extract containing 7% to 12% caffeine has been used safely for up to 2 years (8117,37725). Also decaffeinated green tea extract up to 1.3 grams daily enriched in EGCG has been used safely for up to 12 months (90158,97131). In addition, green tea extract has been safely used as part of an herbal mixture also containing garcinia, coffee, and banaba extracts for 12 weeks (90137). ...when used topically and appropriately as a cream or mouthwash (6065,11310,90141,90150,90151).
POSSIBLY UNSAFE ...when consumed as a beverage in large quantities. Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other significant adverse effects. Doses of caffeine greater than 600 mg per day, or approximately 12 cups of green tea, have been associated with significant adverse effects such as tachyarrhythmias and sleep disturbances (11832). These effects would not be expected to occur with the consumption of decaffeinated green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. There is also some speculation that green tea products containing higher amounts of the catechin epigallocatechin gallate (EGCG) might have increased risk of adverse events. Some research has found that taking green tea products containing EGCG levels greater than 200 mg is associated with increased risk of mild adverse effects such as constipation, increased blood pressure, and rash (90161). Other research has found that doses of EGCG equal to or above 800 mg daily may be associated with increased risk of liver injury in humans (95440,95696,97131).
LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg per kilogram). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, and prior caffeine use (11832).
CHILDREN: POSSIBLY SAFE
when used orally by children and adolescents in amounts commonly found in foods and beverages (4912,11833).
Intake of caffeine in doses of less than 2.5 mg/kg daily is not associated with significant adverse effects in children and adolescents (11733,98806). ...when used for gargling three times daily for up to 90 days (90150).
There is insufficient reliable information available about the safety of green tea extract when used orally in children. However, taking green tea extract orally has been associated with potentially serious, albeit uncommon and unpredictable cases, of hepatotoxicity in adults. Therefore, some experts recommend that children under the age of 18 years of age do not use products containing green tea extract (94897).
PREGNANCY: POSSIBLY SAFE
when used orally in moderate amounts.
Due to the caffeine content of green tea, pregnant patients should closely monitor their intake to ensure moderate consumption. Fetal blood concentrations of caffeine approximate maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,11733,16014,16015,98806). In some studies consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014). This increased risk may be most likely to occur in those with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, most healthy pregnant patients can safely consume doses up to 300 mg daily without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). Advise keeping caffeine consumption below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. Based on animal models, green tea extract catechins are also transferred to the fetus, but in amounts 50-100 times less than maternal concentrations (15010). The potential impact of these catechins on the human fetus is not known, but animal models suggest that the catechins are not teratogenic (15011).
PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts providing more than 300 mg caffeine daily.
Caffeine from green tea crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise keeping caffeine consumption from all sources below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. High maternal doses of caffeine throughout pregnancy have also resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711). However, some research has also found that intrauterine exposure to even modest amounts of caffeine, based on maternal blood levels during the first trimester, is associated with a shorter stature in children ages 4-8 years (109846). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.
There is also concern that consuming large amounts of green tea might have antifolate activity and potentially increase the risk of folic acid deficiency-related birth defects. Catechins in green tea inhibit the enzyme dihydrofolate reductase in vitro (15012). This enzyme is responsible for converting folic acid to its active form. Preliminary evidence suggests that increasing maternal green tea consumption is associated with increased risk of spina bifida (15068). Also, evidence from epidemiological research suggests that serum folate levels in pregnant patients with high green tea intake (57.3 mL per 1000 kcal) are decreased compared to participants who consume moderate or low amounts of green tea (90171). More evidence is needed to determine the safety of using green tea during pregnancy. For now, advise pregnant patients to avoid consuming large quantities of green tea.
LACTATION: POSSIBLY SAFE
when used orally in moderate amounts.
Due to the caffeine content of green tea, nursing parents should closely monitor caffeine intake. Breast milk concentrations of caffeine are thought to be approximately 50% of maternal serum concentrations (9892).
LACTATION: POSSIBLY UNSAFE
when used orally in large amounts.
Consumption of green tea might cause irritability and increased bowel activity in nursing infants (6026). There is insufficient reliable information available about the safety of green tea extracts when applied topically during breast-feeding.
LIKELY SAFE ...when used orally in the amounts commonly found in foods. Jasmine has Generally Recognized as Safe (GRAS) status in the US (4912). There is insufficient reliable information available about the safety of jasmine in medicinal amounts.
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using in amounts greater than those found in food.
POSSIBLY SAFE ...when knotweed is used as a tea in doses up to 6 grams daily of dried plant (2,18) . ...when used topically twice daily for 14 days as a dental rinse containing 1mg/mL knotweed root extract (9347).
PREGNANCY AND LACTATION:
Insufficient reliable information is available; avoid using.
POSSIBLY SAFE ...when used orally and appropriately, short term. Total glucosides of peony has been used with apparent safety in doses of up to 1800 mg daily for up to 12 months (92786,97949,97950,98466,100992,110432,112861,112862). Peony root extract has been used with apparent safety at a dose of 2250 mg daily for up to 3 months (97216). There is insufficient reliable information available about the safety of peony when used orally, topically, or rectally, long-term.
CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term.
Total glucosides of peony has been used with apparent safety in children 1.5-4 years of age at doses up to 180 mg/kg daily or 1.2 grams daily for up to 12 months (92785). Peony root extract 40 mg/kg daily has also been used with apparent safety in children 1-14 years of age for 4 weeks (106851).
PREGNANCY: POSSIBLY UNSAFE
when used orally.
Preliminary research suggests that peony can cause uterine contractions (13400). However, other preliminary research suggests a combination of peony and angelica with or without motherwort, banksias rose, and ligustica, might be safe (11015,48433). Until more is known, avoid use.
LACTATION:
Insufficient reliable information available; avoid using.
POSSIBLY SAFE ...when used orally and appropriately. Schisandra extract up to 1 gram daily has been used for up to 12 weeks with apparent safety (12,96632,105562,105563,112887).
PREGNANCY: POSSIBLY UNSAFE
when used orally.
Some evidence suggests schisandra fruit is a uterine stimulant (11).
LACTATION:
Insufficient reliable information available; avoid using.
Below is general information about the interactions of the known ingredients contained in the product Ginkgo Biloba Herb Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
Theoretically, taking astragalus with antidiabetes drugs might increase the risk of hypoglycemia.
 Details
|
Theoretically, astragalus might interfere with cyclophosphamide therapy.
Details
|
Theoretically, astragalus might interfere with immunosuppressive therapy.
Details
|
Theoretically, astragalus might increase levels and adverse effects of lithium.
Details
Animal research suggests that astragalus has diuretic properties (15103). Theoretically, due to this diuretic effect, astragalus might reduce excretion and increase levels of lithium.
|
Theoretically, ginkgo might decrease the levels and clinical effects of alprazolam.
Details
In clinical research, ginkgo extract (Ginkgold) 120 mg twice daily seems to decrease alprazolam levels by about 17%. However, ginkgo does not appear to decrease the elimination half-life of alprazolam. This suggests that ginkgo is more likely to decrease absorption of alprazolam rather than induce hepatic metabolism of alprazolam (11029).
|
Ginkgo has been shown to increase the risk of bleeding in some people when taken with warfarin. Theoretically, ginkgo might increase the risk of bleeding if used with other anticoagulant or antiplatelet drugs.
Details
Several pharmacodynamic studies suggest that ginkgo inhibits platelet aggregation. It is thought that the ginkgo constituent, ginkgolide B, displaces platelet-activating factor (PAF) from its binding sites, decreasing blood coagulation (6048,9760). Several case reports have documented serious bleeding events in patients taking ginkgo (244,578,579,8581,13002,13135,13179,13194,14456,87868). However, population and clinical studies have produced mixed results. Some evidence shows that short-term use of ginkgo leaf does not significantly reduce platelet aggregation and blood clotting (87732). A study in healthy males who took a specific ginkgo leaf extract (EGb 761) 160 mg twice daily for 7 days found no change in prothrombin time (12114). An analysis of a large medical record database suggests that ginkgo increases the risk of a bleeding adverse event by 38% when taken concurrently with warfarin (91326). It has been suggested that ginkgo has to be taken for at least 2-3 weeks to have a significant effect on platelet aggregation (14811). However, a meta-analysis of 18 studies using standardized ginkgo extracts, 80-480 mg daily for up to 32 weeks, did not find a significant effect on platelet aggregation, fibrinogen concentration, or PT/aPTT (17179). In addition, a single dose of ginkgo plus clopidogrel (14811) or ticlopidine does not seem to significantly increase bleeding time or platelet aggregation (17111,87846). Also, taking ginkgo leaf extract daily for 8 days in conjunction with rivaroxaban does not affect anti-factor Xa activity; however, this study did not evaluate bleeding time (109526).
|
Theoretically, ginkgo might reduce the effectiveness of anticonvulsants.
Details
Ginkgo seeds contain ginkgotoxin. Large amounts of ginkgotoxin can cause neurotoxicity and seizure. Ginkgotoxin is present in much larger amounts in ginkgo seeds than leaves (8232). Ginkgo leaf extract contains trace amounts of ginkgotoxin. The amount of ginkgotoxin in ginkgo leaf and leaf extract seems unlikely to cause toxicity (11296). However, there are anecdotal reports of seizure occurring after use of ginkgo leaf both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy (7030,7090).
|
Theoretically, taking ginkgo with antidiabetes drugs might alter the response to antidiabetes drugs.
Details
Ginkgo leaf extract seems to alter insulin secretion and metabolism, and might affect blood glucose levels in people with type 2 diabetes (5719,14448,103574). The effect of ginkgo seems to differ depending on the insulin and treatment status of the patient. In diet-controlled diabetes patients with hyperinsulinemia, taking ginkgo does not seem to significantly affect insulin or blood glucose levels. In patients with hyperinsulinemia who are treated with oral hypoglycemic agents, taking ginkgo seems to decrease insulin levels and increase blood glucose following an oral glucose tolerance test. Researchers speculate that this could be due to ginkgo-enhanced hepatic metabolism of insulin. In patients with pancreatic exhaustion, taking ginkgo seems to stimulate pancreatic beta-cells, resulting in increased insulin and C-peptide levels, but with no significant change in blood glucose levels in response to an oral glucose tolerance test (14448).
|
Theoretically, ginkgo might decrease the levels and clinical effects of atorvastatin.
Details
In humans, intake of ginkgo extract appears to increase atorvastatin clearance, reducing the area under the curve of atorvastatin by 10% to 14% and the maximum concentration by 29%. However, this interaction does not appear to affect cholesterol synthesis and absorption (89706). Further, a model in rats with hyperlipidemia suggests that administering ginkgo extract does not impact blood levels of atorvastatin and leads to lower total cholesterol, low-density lipoprotein cholesterol, and triglycerides when compared with rats given atorvastatin alone (111331).
|
Theoretically, ginkgo might increase levels of drugs metabolized by CYP1A2.
Details
|
Theoretically, ginkgo might decrease levels of drugs metabolized by CYP2C19.
Details
Some clinical research shows that a specific ginkgo leaf extract (Remembrance, Herbs Product LTD) 140 mg twice daily can induce CYP2C19 enzymes and potentially decrease levels of drugs metabolized by these enzymes (13108). However, other clinical research shows that taking ginkgo 120 mg twice daily for 12 days has no effect on levels of drugs metabolized by CYP2C19 (87824).
|
Theoretically, ginkgo might increase levels of drugs metabolized by CYP2C9.
Details
In vitro, a specific standardized extract of ginkgo leaf (EGb 761) inhibits CYP2C9 activity (11026,12061,14337). The terpenoid (ginkgolides) and flavonoid (quercetin, kaempferol, etc.) constituents seem to be responsible for this effect. Most ginkgo extracts contain some amount of these constituents. Therefore, other ginkgo leaf extracts might also inhibit the CYP2C9 enzyme. However, clinical research suggests that ginkgo might not have a significant effect on CYP2C9 in humans. Ginkgo does not seem to significantly affect the pharmacokinetics of CYP2C9 substrates diclofenac or tolbutamide.
|
Theoretically, ginkgo might decrease levels of drugs metabolized by CYP3A4.
Details
There is conflicting evidence about whether ginkgo induces or inhibits CYP3A4 (1303,6423,6450,11026,87800,87805,111330). Ginkgo does not appear to affect hepatic CYP3A4 (11029). However, it is not known if ginkgo affects intestinal CYP3A4. Preliminary clinical research suggests that taking ginkgo does not significantly affect levels of donepezil, lopinavir, or ritonavir, which are all CYP3A4 substrates (11027,87800,93578). Other clinical research also suggests ginkgo does not significantly affect CYP3A4 activity (10847). However, there are two case reports of decreased efavirenz concentrations and increased viral load in patients taking ginkgo. It is suspected that terpenoids from the ginkgo extract reduced drug levels by inducing cytochrome P450 3A4 (CYP3A4) (16821,25464).
|
Theoretically, ginkgo might decrease the levels and clinical effects of efavirenz.
Details
There are two case reports of decreased efavirenz concentrations and increased viral load in patients taking ginkgo. In one case, an HIV-positive male experienced over a 50% decrease in efavirenz levels over the course of 14 months while taking ginkgo extract. HIV-1 RNA copies also increased substantially, from less than 50 to more than 1500. It is suspected that terpenoids from the ginkgo extract reduced drug levels by inducing cytochrome P450 3A4 (CYP3A4) (16821). In another case report, a patient stable on antiviral therapy including efavirenz for 10 years, had an increase in viral load from <50 copies/mL to 1350 copies/mL after 2 months of taking a combination of supplements including ginkgo. After stopping ginkgo, the viral load was again controlled with the same antiviral therapy regimen (25464).
|
Theoretically, ginkgo might increase the risk of bleeding when used with ibuprofen.
Details
Ginkgo might have antiplatelet effects and has been associated with several case reports of spontaneous bleeding. In one case, a 71-year-old male had taken a specific ginkgo extract (Gingium, Biocur) 40 mg twice daily for 2.5 years. About 4 weeks after starting ibuprofen 600 mg daily he experienced a fatal intracerebral hemorrhage (13179). However, the antiplatelet effects of ginkgo have been questioned. A meta-analysis and other studies have not found a significant antiplatelet effect with standardized ginkgo extracts, 80 mg to 480 mg taken daily for up to 32 weeks (17179).
|
Theoretically, taking ginkgo with oral, but not intravenous, nifedipine might increase levels and adverse effects of nifedipine.
Details
Animal research and some clinical evidence suggests that taking ginkgo leaf extract orally in combination with oral nifedipine might increase nifedipine levels and cause increased side effects, such as headaches, dizziness, and hot flushes (87764,87765). However, taking ginkgo orally does not seem to affect the pharmacokinetics of intravenous nifedipine (87765).
|
Theoretically, taking ginkgo with omeprazole might decrease the levels and clinical effects of omeprazole.
Details
Clinical research shows that a specific ginkgo leaf extract (Remembrance, Herbs Product LTD) 140 mg twice daily can induce cytochrome P450 (CYP) 2C19 enzymes and decrease levels of omeprazole by about 27% to 42% (13108).
|
Theoretically, taking ginkgo with P-glycoprotein substrates might increase the levels and adverse effects of these substrates.
Details
A small clinical study in healthy volunteers shows that using ginkgo leaf extract 120 mg orally three times daily for 14 days can increase levels of the P-glycoprotein substrate, talinolol, by 36% in healthy male individuals. However, single doses of ginkgo do not have the same effect (87830).
|
Theoretically, taking ginkgo with risperidone might increase the levels and adverse effects of risperidone.
Details
A single case of priapism has been reported for a 26-year-old male with schizophrenia who used risperidone 3 mg daily along with ginkgo extract 160 mg daily (87796). Risperidone is metabolized by cytochrome P450 (CYP) 2D6 and CYP3A4. CYP3A4 activity might be affected by ginkgo. Theoretically, ginkgo may inhibit the metabolism of risperidone and increase the risk of adverse effects.
|
Theoretically, ginkgo might decrease the levels and clinical effects of rosiglitazone.
Details
Animal research shows that ginkgo leaf extract orally 100 or 200 mg/kg daily for 10 days alters the pharmacodynamics of rosiglitazone in a dose-dependent manner. The 100 mg/kg and 200 mg/kg doses reduce the area under the concentration time curve (AUC) of rosiglitazone by 39% and 52%, respectively, and the half-life by 28% and 39%, respectively. It is hypothesized that these changes may be due to induction of cytochrome P450 2C8 by ginkgo (109525).
|
Theoretically, taking ginkgo with drugs that lower the seizure threshold might increase the risk for convulsions.
Details
Ginkgo seeds contain ginkgotoxin. Large amounts of ginkgotoxin can cause neurotoxicity and seizure. Ginkgotoxin is present in much larger amounts in ginkgo seeds than leaves (8232). Ginkgo leaf extract contains trace amounts of ginkgotoxin. The amount of ginkgotoxin in ginkgo leaf and leaf extract seems unlikely to cause toxicity (11296). However, there are anecdotal reports of seizure occurring after use of ginkgo leaf both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy (7030,7090,14281).
|
Theoretically, ginkgo might decrease the levels and clinical effects of simvastatin.
Details
Clinical research shows that taking ginkgo extract can reduce the area under the curve and maximum concentration of simvastatin by 32% to 39%. However, ginkgo extract does not seem to affect the cholesterol-lowering ability of simvastatin (89704).
|
Theoretically, ginkgo might increase the levels and clinical effects of sofosbuvir.
Details
Animal research in rats shows that giving a ginkgo extract 25 mg/kg orally daily for 14 days increases the area under the concentration time curve (AUC) after a single sofosbuvir dose of 40 mg/kg by 11%, increases the half-life by 60%, and increases the plasma concentration at 4 hours by 38%. This interaction appears to be related to the inhibition of intestinal P-glycoprotein by ginkgo (109524).
|
Theoretically, ginkgo might increase the blood levels of tacrolimus.
Details
In vitro evidence suggests that certain biflavonoids in ginkgo leaves (i.e. amentoflavone, ginkgetin, bilobetin) may inhibit the metabolism of tacrolimus by up to 50%. This interaction appears to be time-dependent and due to inhibition of cytochrome P450 (CYP) 3A4 by these bioflavonoids. In rats given tacrolimus 1 mg/kg orally, amentoflavone was shown to increase the area under the concentration time curve (AUC) of tacrolimus by 3.8-fold (111330).
|
Taking ginkgo with talinolol seems to increase blood levels of talinolol.
Details
There is some evidence that using ginkgo leaf extract 120 mg orally three times daily for 14 days can increase levels of talinolol by 36% in healthy male individuals. However, single doses of ginkgo do not seem to affect talinolol pharmacokinetics (87830).
|
Theoretically, ginkgo might increase the levels and clinical effects of trazodone.
Details
In a case report, an Alzheimer patient taking trazodone 20 mg twice daily and ginkgo leaf extract 80 mg twice daily for four doses became comatose. The coma was reversed by administration of flumazenil (Romazicon). Coma might have been induced by excessive GABA-ergic activity. Ginkgo flavonoids are thought to have GABA-ergic activity and act directly on benzodiazepine receptors. Ginkgo might also increase metabolism of trazodone to active GABA-ergic metabolites, possibly by inducing cytochrome P450 3A4 (CYP3A4) metabolism (6423).
|
Ginkgo has been shown to increase the risk of bleeding in some people when taken with warfarin.
Details
Several pharmacodynamic studies suggest that ginkgo inhibits platelet aggregation. It is thought that the ginkgo constituent, ginkgolide B, displaces platelet-activating factor (PAF) from its binding sites, decreasing blood coagulation (6048,9760). Several case reports have documented serious bleeding events in patients taking ginkgo (244,576,578,579,8581,13002,13135,13179,13194,14456,87868). Information from a medical database suggests that when taken concurrently with warfarin, ginkgo increases the risk of a bleeding adverse event by 38% (91326). There is also some evidence that ginkgo leaf extract can inhibit cytochrome P450 2C9, an enzyme that metabolizes warfarin. This could result in increased warfarin levels (12061). However, population and clinical research has produced mixed results. Clinical research in healthy people suggests that ginkgo has no effect on INR, or the pharmacokinetics or pharmacodynamics of warfarin (12881,15176,87727,87889). A meta-analysis of 18 studies using standardized ginkgo extracts, 80 mg to 480 mg daily for up to 32 weeks, did not find a significant effect on platelet aggregation, fibrinogen concentration, or PT/aPTT (17179). There is also some preliminary clinical research that suggests ginkgo might not significantly increase the effects of warfarin in patients that have a stable INR (11905).
|
Theoretically, high doses of green tea might increase the effects and side effects of 5-fluorouracil.
Details
Animal research shows that taking green tea in amounts equivalent to about 6 cups daily in humans for 4 weeks prior to receiving a single injection of 5-fluorouracil increases the maximum plasma levels of 5-fluorouracil by about 2.5-fold and the area under the curve by 425% (98424).
|
Theoretically, green tea might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Details
Green tea contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine doesn't seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).
|
Theoretically, alcohol might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Concomitant use of alcohol and caffeine can increase caffeine serum concentrations and the risk of caffeine adverse effects. Alcohol reduces caffeine metabolism (6370).
|
Theoretically, green tea may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Details
Conflicting reports exist regarding the effect of green tea on bleeding risk when used with anticoagulant or antiplatelet drugs; however, most evidence suggests that drinking green tea in moderate amounts is unlikely to cause a significant interaction. Green tea contains small amounts of vitamin K, approximately 7 mcg per cup (100524). Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea (1460,1461,1463,4211,6048,8028,20868). However, these reports are rare, and very large doses of green tea (about 8-16 cups daily) appear to be needed to cause these effects. Furthermore, the catechins and caffeine in green tea are reported to have antiplatelet activity (733,8028,8029,12882,100524).
|
Theoretically, taking green tea with antidiabetes drugs might interfere with blood glucose control.
Details
|
Green tea extract seems to reduce the levels and clinical effects of atorvastatin.
Details
In healthy humans, taking green tea extract 300 mg or 600 mg along with atorvastatin reduces plasma levels of atorvastatin by approximately 24%. The elimination of atorvastatin is not affected (102714). Atorvastatin is a substrate of organic anion-transporting polypeptides (OATPs). Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs. Some OATPs are expressed in the small intestine and are responsible for the uptake of drugs and other compounds, which may have resulted in reduced plasma levels of atorvastatin (19079). It is not clear if drinking green tea alters the absorption of atorvastatin.
|
Green tea contains caffeine. Theoretically, concomitant use of large amounts of caffeine might increase cardiac inotropic effects of beta-agonists (15).
|
Theoretically, green tea might interfere with the effects of bortezomib.
Details
In vitro research shows that green tea polyphenols, such as epigallocatechin gallate (EGCG), interact with bortezomib and block its proteasome inhibitory action. This prevents the induction of cell death in multiple myeloma or glioblastoma cancer cell lines (17212). Advise patients taking bortezomib, not to take green tea.
|
Theoretically, green tea might reduce the effects of carbamazepine and increase the risk for convulsions.
Details
Green tea contains caffeine. Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg (23559,23561). Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals (23562).
|
Theoretically, green tea might reduce the levels and clinical effects of celiprolol.
Details
In a small human study, taking green tea daily for 4 days appears to decrease blood and urine levels of celiprolol by at least 98% (104607). This interaction is possibly due to the inhibition of organic anion transporting polypeptide (OATP). Green tea catechins have been shown to inhibit organic anion transporting polypeptides (OATP), one of which, OATP1A2, is found in the intestine (19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).
|
Theoretically, concomitant use might increase the effects and adverse effects of caffeine in green tea.
Details
Green tea contains caffeine. Cimetidine can reduce caffeine clearance by 31% to 42% (11736).
|
Theoretically, green tea might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Details
Animal research suggests that, although green tea extract does not affect the elimination of clozapine, it delays the time to reach peak concentration and reduces the peak plasma levels (90173). Also, concomitant administration of green tea and clozapine might theoretically cause acute exacerbation of psychotic symptoms due to the caffeine in green tea. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg daily inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Researchers speculate that caffeine might inhibit CYP1A2. However, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients be more sensitive to the interaction between clozapine and caffeine (13741).
|
Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in green tea.
Details
Green tea contains caffeine. Oral contraceptives can decrease caffeine clearance by 40% to 65% (8644).
|
Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2) (3941,5051,11741,23557,23573,23580,24958,24959,24960,24962), (24964,24965,24967,24968,24969,24971,38081,48603). Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from green tea and increase caffeine levels.
|
Green tea is unlikely to produce clinically significant changes in the levels and clinical effects of CYP3A4 substrates.
Details
|
Theoretically, green tea might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Details
Green tea contains caffeine. Caffeine might inhibit dipyridamole-induced vasodilation (11770,11772). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).
|
Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
Details
In human research, disulfiram decreases the clearance and increases the half-life of caffeine (11840).
|
Theoretically, using green tea with diuretic drugs might increase the risk of hypokalemia.
Details
|
Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Details
|
Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Estrogen inhibits caffeine metabolism (2714).
|
Theoretically, green tea might reduce the effects of ethosuximide and increase the risk for convulsions.
Details
Green tea contains caffeine. Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide (23560). However, this effect has not been reported in humans.
|
Theoretically, green tea might reduce the effects of felbamate and increase the risk for convulsions.
Details
Green tea contains caffeine. Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate (23563). However, this effect has not been reported in humans.
|
Green tea can decrease blood levels of fexofenadine.
Details
Clinical research shows that green tea can significantly decrease blood levels and excretion of fexofenadine. Taking green tea extract with a dose of fexofenadine decreased bioavailability of fexofenadine by about 30%. In vitro, green tea inhibits the cellular accumulation of fexofenadine by inhibiting the organic anion transporting polypeptide (OATP) drug transporter (111029). Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs, specifically OATP1A2, OATP1B1, and OATP2B1. In addition, green tea has been shown to reduce the absorption of some drugs that are OATP substrates (19079,102714,102730).
|
Theoretically, fluconazole might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Fluconazole decreases caffeine clearance by approximately 25% (11022).
|
Theoretically, green tea might increase the levels and adverse effects of flutamide.
Details
Green tea contains caffeine. In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide (23553). Theoretically, concomitant use of caffeine and flutamide might increase serum concentrations of flutamide and increase the risk adverse effects.
|
Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Fluvoxamine reduces caffeine metabolism (6370).
|
Theoretically, concomitant use might have additive adverse hepatotoxic effects.
Details
|
Theoretically, green tea might reduce the levels and clinical effects of imatinib.
Details
In animal research, a single dose of green tea extract reduces the area under the curve (AUC) of imatinib by up to approximately 64% and its main metabolite N-desmethyl imatinib by up to approximately 81% (104600). This interaction has not been shown in humans. The mechanism of action is unclear but may involve multiple pathways.
|
Theoretically, green tea might reduce the levels and clinical effects of lisinopril.
Details
Preliminary clinical research shows that a single dose of green tea extract reduces plasma concentrations of lisinopril. Compared to a control group, peak levels and area under the curve (AUC) of lisinopril were reduced by approximately 71% and 66%, respectively (104599). This may be due to inhibition of organic anion transporting polypeptides (OATP) by green tea catechins (19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).
|
Theoretically, abrupt green tea withdrawal might increase the levels and adverse effects of lithium.
Details
|
Theoretically, metformin might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Animal research suggests that metformin can reduce caffeine metabolism (23571). Theoretically, concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.
|
Theoretically, methoxsalen might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Methoxsalen can reduce caffeine metabolism (23572). Concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.
|
Theoretically, mexiletine might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Mexiletine can decrease caffeine elimination by 50% (1260).
|
Theoretically, green tea might increase the levels and adverse effects of midazolam.
Details
Animal research suggests that green tea extract can increase the maximum plasma concentration, but not the half-life, of oral midazolam. This effect has been attributed to the inhibition of intestinal cytochrome P450 3A4 (CYP3A4) and induction of hepatic CYP3A4 enzymes by green tea constituents (20896). However, it is unlikely that this effect is clinically significant, as the dose used in animals was 50 times greater than what is commonly ingested by humans.
|
Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Details
Green tea contains caffeine. Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.
|
Green tea seems to reduce the levels and clinical effects of nadolol.
Details
Preliminary clinical research shows that green tea consumption reduces plasma concentrations of nadolol. Compared to a control group, both peak levels and total drug exposure (AUC) of nadolol were reduced by approximately 85% in subjects who drank green tea daily for two weeks. Drinking green tea with nadolol also significantly reduced nadolol's systolic blood pressure lowering effect (19071). Other clinical research shows that a single dose of green tea can affect plasma nadolol levels for at least one hour (102721). Green tea catechins have been shown to inhibit organic anion transporting polypeptides (OATP), one of which, OATP1A2, is involved in the uptake of nadolol in the intestine (19071,19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).
|
Theoretically, green tea might increase the levels and adverse effects of nicardipine.
Details
Green tea contains EGCG. Animal research shows that EGCG increases the area under the curve (AUC) and absolute oral bioavailability of nicardipine. The mechanism of action is thought to involve inhibition of both intestinal P-glycoprotein and hepatic cytochrome P450 3A (90136). The effect of green tea itself on nicardipine is unclear.
|
Theoretically, concomitant use might increase the risk of hypertension.
Details
Green tea contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).
|
Green tea seems to reduce the levels of nintedanib.
Details
Clinical research shows that green tea can significantly decrease blood levels of nintedanib. Taking green tea extract twice daily for 7 days 30 minutes prior to a meal along with nintedanib with the meal decreased the 12-hour area under the curve (AUC) values for nintedanib by 21%. There was no effect on the maximum concentration of nintedanib (111028).
|
Theoretically, green tea might reduce the absorption of organic anion-transporting polypeptide (OATP) substrates.
Details
OATPs are expressed in the small intestine and liver and are responsible for the uptake of drugs and other compounds. Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs, specifically OATP1A2, OATP1B1, and OATP2B1. In addition, green tea has been shown to reduce the absorption of some drugs that are OATP substrates, including lisinopril and celiprolol (19079,102714,102730).
|
Theoretically, green tea might decrease the effects of pentobarbital.
Details
Green tea contains caffeine. Theoretically, caffeine might negate the hypnotic effects of pentobarbital (13742).
|
Theoretically, green tea might reduce the effects of phenobarbital and increase the risk for convulsions.
Details
|
Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.
Details
|
Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Details
|
Theoretically, green tea might reduce the effects of phenytoin and increase the risk for convulsions.
Details
|
Theoretically, green tea might increase the levels and clinical effects of pioglitazone.
Details
Green tea contains caffeine. Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.
|
Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
Details
|
Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Details
Green tea contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2, and concomitant use might reduce metabolism of one or both agents (11739).
|
Theoretically, green tea extract might alter the absorption and distribution of rosuvastatin.
Details
In animal research, giving green tea extract with rosuvastatin increased plasma levels of rosuvastatin. Rosuvastatin is a substrate of organic anion-transporting polypeptide (OATP)1B1, which is expressed in the liver. The increased plasma levels may have been related to inhibition of OATP1B1 (102717). However, in humans, taking EGCG with rosuvastatin reduced plasma levels of rosuvastatin, suggesting an inhibition of intestinal OATP (102730). It is not clear if drinking green tea alters the absorption of rosuvastatin.
|
Theoretically, concomitant use might increase stimulant adverse effects.
Details
Green tea contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).
|
Theoretically, terbinafine might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).
|
Theoretically, green tea might increase the levels and adverse effects of theophylline.
Details
Green tea contains caffeine. Large amounts of caffeine might inhibit theophylline metabolism (11741).
|
Theoretically, green tea might increase the levels and adverse effects of tiagabine.
Details
Green tea contains caffeine. Animal research suggests that chronic caffeine administration can increase the serum concentrations of tiagabine. However, concomitant use does not seem to reduce the antiepileptic effects of tiagabine (23561).
|
Theoretically, ticlopidine might increase the levels and adverse effects of caffeine.
Details
Green tea contains caffeine. In vitro evidence suggests that ticlopidine can inhibit caffeine metabolism (23557). However, this effect has not been reported in humans.
|
Theoretically, green tea might reduce the effects of valproate and increase the risk for convulsions.
Details
|
Theoretically, concomitant use might increase the levels and adverse effects of both verapamil and caffeine.
Details
Animal research suggests that the green tea constituent EGCG increases the area under the curve (AUC) values for verapamil by up to 111% and its metabolite norverapamil by up to 87%, likely by inhibiting P-glycoprotein (90138). Also, theoretically, concomitant use of verapamil and caffeinated beverages such as green tea might increase plasma caffeine concentrations and the risk of adverse effects, due to the caffeine contained in green tea. Verapamil increases plasma caffeine concentrations by 25% (11741).
|
Theoretically, green tea may increase the risk of bleeding if used with warfarin.
Details
Conflicting reports exist regarding the potential of green tea to antagonize the effect of warfarin; however, most evidence suggests that drinking green tea in moderation is unlikely to cause a significant interaction. Green tea contains a small amount of vitamin K, approximately 7 mcg per cup (100524). Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea (1460,1461,1463,4211,6048,8028,20868). However, these reports are rare, and very large doses of green tea (about 8-16 cups daily) appear to be needed to cause these effects (1460,1461,1463,8028). Therefore, use of green tea in moderate amounts is unlikely to antagonize the effects of warfarin; however, very large doses should be avoided.
|
Theoretically, combining peony with anticoagulant or antiplatelet drugs might increase the risk of bleeding.
Details
In vitro research suggests that peony might have antiplatelet, anticoagulant, and antithrombotic effects (92787).
|
Theoretically, peony might increase the levels and clinical effects of clozapine.
Details
In vitro research shows that peony suppresses the metabolism of clozapine via weak-to-moderate inhibitory effects on cytochromes P450 (CYP) 1A2 and CYP3A4 (92790). This effect has not been reported in humans.
|
Theoretically, peony might interfere with contraceptive drugs due to competition for estrogen receptors.
Details
In vitro and animal research shows that peony extract has estrogenic activity (100990). Concomitant use might also increase the risk for estrogen-related adverse effects.
|
Theoretically, use of peony may increase the levels and clinical effects of drugs metabolized by CYP1A2.
Details
In vitro research shows that peony suppresses the metabolism of clozapine via weak-to-moderate inhibitory effects on CYP1A2 and CYP3A4 (92790). This effect has not been reported in humans.
|
Theoretically, use of peony may increase the levels and clinical effects of drugs metabolized by CYP3A4.
Details
In vitro research shows that peony suppresses the metabolism of clozapine via weak-to-moderate inhibitory effects on CYP1A2 and CYP3A4 (92790). This effect has not been reported in humans.
|
Theoretically, concomitant use of large amounts of peony might interfere with hormone replacement therapy and/or increase the risk for estrogen-related adverse effects.
Details
In vitro and animal research shows that peony extract has estrogenic activity (100990). Theoretically, peony might compete for estrogen receptors and/or cause additive estrogenic effects.
|
Theoretically, peony might reduce the levels and clinical effects of phenytoin.
Details
Animal research shows that taking peony root reduces levels of phenytoin (8657). Some researchers suggest that peony root might affect cytochrome P450 (CYP) 2C9, which metabolizes phenytoin. However, preliminary research in humans shows that peony root does not alter levels of losartan (Cozaar), which is also metabolized by CYP2C9 (11480).
|
Theoretically, schisandra might increase the levels and clinical effects of cyclophosphamide.
Details
In vitro research shows that schisandra increases the concentration of cyclophosphamide, likely through inhibition of cytochrome P450 3A4. After multiple doses of the schisandra constituents schisandrin A and schisantherin A, the maximum concentration of cyclophosphamide was increased by 7% and 75%, respectively, while the overall exposure to cyclophosphamide was increased by 29% and 301%, respectively (109636).
|
Schisandra can increase the levels and clinical effects of cyclosporine.
Details
A small observational study in children with aplastic anemia found that taking schisandra with cyclosporine increased cyclosporine trough levels by 93% without increasing the risk of adverse events. However, the dose of cyclosporine was reduced in 9% of children to maintain appropriate cyclosporine blood concentrations (109637).
|
Theoretically, schisandra might increase the levels and clinical effects of CYP2C19 substrates.
Details
In vitro research shows that schisandra inhibits CYP2C19, and animal research shows that schisandra increases the concentration of voriconazole, a CYP2C19 substrate (105566). Theoretically, schisandra may also inhibit the metabolism of other CYP2C19 substrates. This effect has not been reported in humans.
|
Theoretically, schisandra might decrease the levels and clinical effects of CYP2C9 substrates.
Details
In vitro and animal research suggests that schisandra induces CYP2C9 enzymes (14441). This effect has not been reported in humans.
|
Schisandra can increase the levels and clinical effects of drugs metabolized by CYP3A4.
Details
Most clinical and laboratory research shows that schisandra, administered either as a single dose or up to twice daily for 14 days, inhibits CYP3A4 and increases the concentration of CYP3A4 substrates such as cyclophosphamide, midazolam, tacrolimus, and talinolol (13220,17414,23717,91386,91388,91387,96631,105564,109636,109638,109639,109640,109641). Although one in vitro and animal study shows that schisandra may induce CYP3A4 metabolism (14441), this effect appears to be overpowered by schisandra's CYP3A4 inhibitory activity and has not been reported in humans.
|
Schisandra can increase the levels and clinical effects of midazolam.
Details
A small pharmacokinetic study in healthy adults shows that taking schisandra extract (Hezheng Pharmaceutical Co.) containing deoxyschizandrin 33.75 mg twice daily for 8 days and a single dose of midazolam 15 mg on day 8 increases the overall exposure to midazolam by about 119%, increases the peak plasma level of midazolam by 86%, and decreases midazolam clearance by about 52%. This effect has been attributed to inhibition of CYP3A4 by schisandra (91388).
|
Schisandra might increase the levels and clinical effects of P-glycoprotein substrates.
Details
In vitro research shows that schisandra extracts and constituents such as schisandrin B inhibit P-glycoprotein mediated efflux in intestinal cells and in P-glycoprotein over-expressing cell lines (17414,105643,105644). Additionally, a small clinical study shows that schisandra increases the peak concentration and overall exposure to talinolol, a P-glycoprotein probe substrate (91386). Theoretically, schisandra might inhibit the efflux of other P-glycoprotein substrates.
|
Schisandra can increase the levels and clinical effects of sirolimus.
Details
A small pharmacokinetic study in healthy volunteers shows that taking 3 capsules of schisandra (Hezheng Pharmaceutical Company) containing a total of 33.75 mg deoxyschizandrin twice daily for 13 days and then taking a single dose of sirolimus 2 mg increases the overall exposure and peak level of sirolimus by two-fold. This effect is thought to be due to inhibition of cytochrome P450 3A4 by schisandra, as well as possible inhibition of the P-glycoprotein drug transporter (105643).
|
Schisandra can increase the levels and clinical effects of tacrolimus.
Details
Clinical research in healthy children and adults, transplant patients, and patients with nephrotic syndrome and various rheumatic immunologic disorders shows that taking schisandra with tacrolimus increases tacrolimus peak levels by 183% to 268%, prolongs or delays time to peak tacrolimus concentrations, increases overall exposure to tacrolimus by 126% to 343%, and decreases tacrolimus clearance by 19% to 73% (17414,91387,15570,96631,105623,109638,109639,109640,109641,112889)(112890,112972,112973,112974). This effect is thought to be due to inhibition of P-glycoprotein drug transporter and CYP3A4 and CYP3A5 by schisandra (17414,96631,105623,105643,105644,112974). Some clinical and observational studies suggest that schisandra increases tacrolimus levels similarly in both expressors and non-expressors of CYP3A5, while other studies suggest it does so to a greater degree in CYP3A5 expressors than non-expressors (105623,109638,109639,109640,112889,112890,112973,112974). Animal research suggests that the greatest increase in tacrolimus levels occurs when schisandra is taken either concomitantly or up to 2 hours before tacrolimus (105564), and clinical and observational research in humans suggests that schisandra may increase whole blood levels of tacrolimus and decrease clearance of tacrolimus in a dose-dependent manner (109639,109640,112972).
|
Schisandra can increase the levels and clinical effects of talinolol.
Details
A small pharmacokinetic study in healthy volunteers shows that taking schisandra extract 300 mg twice daily for 14 days with a single dose of talinolol 100 mg on day 14 increases the peak talinolol level by 51% and the overall exposure to talinolol by 47%. This effect is thought to be due to the possible inhibition of cytochrome P450 3A4 and P-glycoprotein by schisandra (91386).
tly.
|
Theoretically, schisandra might increase the levels and clinical effects of voriconazole.
Details
Animal research shows that oral schisandra given daily for 1 or 14 days increases levels of intravenously administered voriconazole, a cytochrome P450 (CYP) 2C19 substrate. This effect is thought to be due to inhibition of CYP2C19 by schisandra (105566). However, this interaction has not been reported in humans.
|
Theoretically, schisandra might decrease the levels and clinical effects of warfarin.
Details
Animal research suggests that oral schisandra extract, given daily for 6 days, reduces levels of intravenously administered warfarin. This effect might be due to the induction of cytochrome P450 (CYP) 2C9 metabolism by schisandra (14441). However, this interaction has not been reported in humans.
|
Below is general information about the adverse effects of the known ingredients contained in the product Ginkgo Biloba Herb Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
General
...Orally and intravenously, astragalus root seems to be well tolerated.
Topically, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.
Serious Adverse Effects (Rare):
Orally: A case report raises concerns about liver and kidney cysts with astragalus use.
Cardiovascular ...Orally, astragalus has reportedly been associated with lacunar angina in one clinical trial. However, this may not have been caused by astragalus (17355). In addition, rapid intravenous administration of astragalus has resulted in temporary palpitations (32812).
Dermatologic ...Intravenously, astragalus may cause rash, eczema, and pruritus (33034).
Gastrointestinal ...Orally, astragalus has reportedly been associated with enterocolitis and nausea in one clinical trial. However, these effects may not have been caused by astragalus (17355).
Genitourinary ...Orally, astragalus has reportedly been associated with vulvitis in one clinical trial. However, this effect may not have been caused by astragalus (17355).
Hepatic ...A case of high serum CA19-9 levels and small liver and kidney cysts has been reported for a 38-year-old woman who drank astragalus tea daily for one month. Levels returned to normal after one month, and cysts disappeared after ten months. Both symptoms returned following a resumption of astragalus use. The authors state that astragalus was the likely cause given the temporal relationship (90658).
Musculoskeletal ...Orally, astragalus has been associated with reports of musculoskeletal pain in one clinical trial. However, these effects may not have been caused by astragalus (114803).
Neurologic/CNS ...Intravenously, administration of astragalus has been associated with temporary dizziness in patients with heart failure in clinical research (32812,114804). Orally, astragalus has also been associated with dizziness in one clinical study. However, these effects may not have been caused by astragalus (114803).
Pulmonary/Respiratory ...Orally, astragalus has reportedly been associated with rhinosinusitis and pharyngitis in one clinical trial. However, these effects may not have been caused by astragalus (17355).
Renal ...A case of high serum CA19-9 levels and small liver and kidney cysts has been reported for a 38-year-old woman who drank astragalus tea daily for one month. Levels returned to normal after one month, and cysts disappeared after ten months. Both symptoms returned following a resumption of astragalus use. The authors state that astragalus was the likely cause given the temporal relationship (90658).
General
...Orally, ginkgo leaf extract is generally well tolerated when used for up to 6 years.
However, the seed and crude plant contain toxic constituents and should be avoided.
Intravenously, ginkgo leaf extract seems to be well tolerated when used for up to 30 days.
Topically, no adverse effects have been reported with ginkgo as a single ingredient. However, a thorough evaluation of safety outcomes has not been conducted.
Most Common Adverse Effects:
Orally: Dizziness, gastrointestinal symptoms, headache.
Serious Adverse Effects (Rare):
Orally: Arrhythmia, bleeding, Stevens-Johnson syndrome.
Cardiovascular
...Cardiac arrhythmias suspected to be related to ginkgo have been reported.
Internationally, there are at least 162 reports from 18 countries, with 34% of cases considered serious, involving five deaths and four life-threatening events. Additionally, a report from Canada found that 10 out of 15 cases of arrhythmia were considered serious. Ginkgo was the only suspect ingredient in 57% of all international reports, with symptoms generally presenting within days of initiation. The most common symptoms included palpitations, tachycardia, bradycardia, syncope, and loss of consciousness. Most cases were reported to be related to oral use of ginkgo leaf products; however, some cases were associated with oral use of the seed, and others with intravenous or intramuscular use of the leaf. Documented discontinuation of ginkgo led to recovery in approximately 84% of cases where ginkgo was the sole suspect. Despite these findings, ginkgo cannot be confirmed as the causal agent. It is possible that these reports are confounded by underlying co-morbidities. Of the reported cases, the main reason for ginkgo use was tinnitus, a symptom commonly associated with pre-existing arrhythmias (105253,105254). Despite this large number of reports, only three cases of cardiac arrhythmia have been published in the literature (105253,105254). In one case, frequent nocturnal episodes of paroxysmal atrial fibrillation were reported for a 35-year-old female taking ginkgo extract 240 mg daily orally for 2 months. Arrythmias ceased following discontinuation of ginkgo (87884).
In one clinical trial, the rate of ischemic stroke and transient ischemic attacks was significantly higher in patients taking ginkgo extract orally when compared with placebo (16635). It is unclear if these events were due to ginkgo, other factors, or a combination.
Dermatologic ...Topically, ginkgo fruit pulp can cause contact dermatitis, with intense itching, edema, papules, and pustules which take 7-10 days to resolve after stopping contact (112946).
Gastrointestinal
...Orally, ginkgo extract may cause mild gastrointestinal discomfort or pain (3965,8543,17112,87818,87858), nausea and vomiting (8543,17112,87728,87844,87858), diarrhea (87844), dry mouth (17112), and constipation (5719,87787).
However, post-market surveillance suggests that the incidence of these events is relatively low, occurring in less than 2% of patients (88007).
Fresh ginkgo seeds can cause stomach ache, nausea, vomiting, or diarrhea. Ingesting roasted seeds in amounts larger than the normal food amounts of 8-10 seeds per day, or long-term, can also cause these same adverse reactions (8231,8232).
Genitourinary ...Orally, ginkgo extract has been reported to cause blood in the urine in one patient (87858).
Hematologic
...Spontaneous bleeding is one of the most concerning potential side effects associated with ginkgo.
There are several published case reports linking ginkgo to episodes of minor to severe bleeding; however, not all case reports clearly establish ginkgo as the cause of bleeding. In most cases, other bleeding risk factors were also present including taking other medications or natural medicines, old age, liver cirrhosis, recent surgery, and other conditions. In most cases, bleeding occurred after several weeks or months of taking ginkgo (13135). Large-scale clinical trials and a meta-analysis evaluating standardized ginkgo leaf extracts show that the incidence of bleeding in patients taking ginkgo is not significantly higher than in those taking placebo (16634,16635,17179,17402).
There are several case reports of intracerebral bleeding. Some of these cases resulted in permanent neurological damage and one case resulted in death (244,578,8581,13135,13179,14456,87868,87977).
There are at least 4 cases of ocular bleeding including spontaneous hyphema (bleeding from the iris into the anterior part of the eye) and retrobulbar hemorrhage associated with ginkgo use (579,10450,13135).
There are also cases of surgical and post-surgical complications in patients using ginkgo. Retrobulbar hemorrhage (bleeding behind the eye) during cataract surgery has been associated with ginkgo use (10450). Excessive postoperative bleeding requiring transfusion has also occurred following laparoscopic surgery in a patient who had been taking ginkgo leaf extract (887). There have also been two cases of excessive bleeding during surgery and post-surgical hematoma in patients undergoing rhytidoplasty and blepharoplasty (13002). In another case, an elderly patient taking ginkgo experienced excessive postoperative bleeding following total hip arthroplasty (13194). In another case, use of ginkgo following liver transplantation surgery was associated with subphrenic hematoma requiring evacuation by laparotomy. The patient also subsequently experienced vitreous hemorrhage (14315). In another case, an elderly patient who had taken ginkgo chronically experienced excessive post-operative bleeding following an ambulatory surgical procedure (14453).
In another case, an elderly man experienced nose bleeds and ecchymosis following use of ginkgo. One case of diffuse alveolar hemorrhage in a female taking ginkgo and ginseng for over one year has been reported (95670). These instances of bleeding stopped when ginkgo was discontinued, and recurred when the patient started taking ginkgo again (13135).
Persistent bleeding has also occurred following dental surgery (87862) and laparoscopic cholecystectomy (88000). Nosebleed has also been reported as an adverse effect in a clinical trial (87813).
Immunologic ...Orally, ginkgo leaf extract can cause allergic skin reactions in some patients (14449,15578,112946). In one case, a patient developed acute generalized exanthematous pustulosis 48 hours after taking a single-ingredient ginkgo product. The rash resolved within 10 days after discontinuing ginkgo (14449). In another case, progressive erythema of the face, neck, trunk, and extremities occurred after two 60 mg oral doses of ginkgo extract (112946). There is also a case of Stevens-Johnson syndrome following a second administration of a preparation containing ginkgo leaf extract, choline, vitamin B6, and vitamin B12 (208). In another case, systemic edema and severe arthralgia was reported after contact with a ginkgo tree nut and manifested as multifocal lymphadenopathy associated with an allergic reaction on PET/CT scan imaging (95672).
Musculoskeletal ...Edema has been reported for three patients treated with ginkgo extract 40 mg orally three times daily (87818).
Neurologic/CNS ...Orally, ginkgo extract may cause headache (6220,8543,87818), dizziness (5719,87818), increased desire to sleep (87839), and sedation (10893) in some patients. In addition, although ginkgo leaf and ginkgo leaf extract contain only small amounts of ginkgotoxin, there are anecdotal reports of seizure occurring after use of ginkgo leaf preparations both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy (7030,7090,11296,14281).
Ocular/Otic
...Orally, ginkgo extract may cause tinnitus is some patients, although the incidence is rare (8543).
Topically, eye drops containing ginkgo extract and hyaluronic acid may cause stinging sensations in some people (87829).
Psychiatric ...Orally, ginkgo has been associated with a single case of mood dysregulation. A 50-year-old female with schizophrenia developed irritability, difficulty controlling anger, and agitation after one week of taking ginkgo 80 mg twice daily. The mood changes resolved within 2-3 days of discontinuation. When ginkgo was re-trialed at a later date, the same symptoms reappeared, and again dissipated after discontinuation of the ginkgo product. The relationship between ginkgo and mood dysregulation was considered to be "probable" based on the Naranjo adverse drug reaction probability scale (96763); however, the exact mechanism by which ginkgo may have affected mood regulation is unknown.
General
...Orally, green tea is generally well tolerated when consumed as a beverage in moderate amounts.
Green tea extract also seems to be well tolerated when used for up to 12 months.
Most Common Adverse Effects:
Orally: Bloating, constipation, diarrhea, dyspepsia, flatulence, and nausea.
Serious Adverse Effects (Rare):
Orally: Hepatotoxicity, hypokalemia, and thrombotic thrombocytopenic purpura have been reported rarely.
Cardiovascular
...Acute or short-term oral administration of green tea may cause hypertension (53719,54014,54065,54076,102716).
The risk may be greater for green tea products containing more than 200 mg epigallocatechin gallate (EGCG) (90161). However, consumption of brewed green tea does not seem to increase blood pressure or pulse, even in mildly hypertensive patients (1451,1452). In fact, some evidence suggests that habitual tea consumption is associated with a reduced risk of developing hypertension (12518). Also, epidemiological research suggests there is no association of caffeine consumption with incidence of hypertension or with cardiovascular disease mortality in patients with hypertension (13739,111027). Rarely, green tea consumption may cause hypotension (53867).
Epidemiological research suggests that regular caffeine intake of up to 400 mg per day, or approximately 8 cups of green tea, is not associated with an increased incidence of atrial fibrillation (38018,38076,91028,91034,97451,97453), atherosclerosis (38033), cardiac ectopy (91127), stroke (37804), ventricular arrhythmia (95948,97453), and cardiovascular disease in general (37805,98806).
Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, and temporary loss of consciousness has been associated with the combined use of ephedra and caffeine (2729). There is also a report of ischemic stroke in an athlete who consumed ephedra 40-60 mg, creatine monohydrate 6 grams, caffeine 400-600 mg, and a variety of other supplements daily for 6 weeks (1275). In theory, combining caffeinated green tea with ephedra would have similar effects.
In a case report, the EGCG component of a specific weight loss supplement (Hydroxycut) was thought to be responsible for atrial fibrillation (54028). The patient was given two doses of intravenous diltiazem and was loaded with intravenous digoxin. Thirty-six hours after the last product dose, she spontaneously converted to normal sinus rhythm. The authors suggested that the block of the atrial-specific KCNA5 potassium channel likely played a role in this response.
A case of thrombotic thrombocytopenic purpura has been reported for a patient who consumed a weight loss product containing green tea (53978). She presented at the emergency department with a one-week history of malaise, fatigue, and petechiae of the skin. Twelve procedures of plasmapheresis were performed, and corticosteroid treatment was initiated. She was discharged after 20 days.
Dermatologic ...Orally, green tea may cause skin rashes or skin irritation (53731,54038,90161,90187,102716). Topically, green tea may cause local skin reactions or skin irritation, erythema, burning, itching, edema, and erosion (53731,54018,97136,104609,111031). A green tea extract ointment applied to the cervix can cause cervical and vaginal inflammation, vaginal irritation, and vulval burning (11310,36442,36438). When applied to external genital or perianal warts, a specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins can cause erythema, pruritus, local pain, discomfort and burning, ulceration, induration, edema, and vesicular rash (15067,53907).
Endocrine
...There is some concern that, due to its caffeine content, green tea may be associated with an increased risk of fibrocystic breast disease, breast cancer, and endometriosis.
However, this is controversial since findings are conflicting (8043). Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996).
A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages, such as green tea, and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).
A case of hypoglycemia has been reported for a clinical trial participant with type 2 diabetes who used green tea in combination with prescribed antidiabetes medication (54035).
Gastrointestinal ...Orally, green tea beverage or supplements can cause nausea, vomiting, abdominal bloating and pain, constipation, dyspepsia, reflux, morning anorexia, increased thirst, flatulence, and diarrhea. These effects are more common with higher doses of green tea or green tea extract, equivalent to 5-6 liters of tea per day (8117,11366,36398,53719,53867,53936,54038,54076,90139,90140)(90161,90175,90187,97131,97136,102716).
Hepatic
...There is concern that some green tea products, especially green tea extracts, can cause hepatotoxicity in some patients.
In 2017, the regulatory agency Health Canada re-issued a warning to consumers about this concern. The updated warning advises patients taking green tea extracts, especially those with liver disease, to watch for signs of liver toxicity. It also urges children to avoid taking products containing green tea extracts (94897). In 2020, the United States Pharmacopeia (USP) formed an expert panel to review concerns of green tea extract-related hepatotoxicity. Based on their findings, USP determined that any products claiming compliance with USP quality standards for green tea extract must include a specific warning on the label stating "Do not take on an empty stomach. Take with food. Do not use if you have a liver problem and discontinue use and consult a healthcare practitioner if you develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes)" (102722).
Numerous case reports of hepatotoxicity, primarily linked to green tea extract products taken in pill form, have been published. A minimum of 29 cases have been deemed at least probably related to green tea and 38 have been deemed possibly related. In addition, elevated liver enzymes have been reported in clinical research (14136,15026,53740,53746,53775,53859,54027,90139,90162,90164)(93256,94898,94899,102716,102720,102722,107158,111020). Most cases of toxicity have had an acute hepatitis-like presentation with a hepatocellular-elevation of liver enzymes and some cholestasis. Onset of hepatotoxic symptoms usually occurs within 3 months after initiation of the green tea extract supplement, and symptoms can persist from 10 days to 1 year (95439,94897,94898,107158). Some reports of hepatotoxicity have been associated with consumption of green tea-containing beverages as well (15026,53742,54016,90125,90143).
In most cases, liver function returned to normal after discontinuation of the green tea product (14136,15026,53859,93256,107158). In one case, use of a specific ethanolic green tea extract (Exolise, Arkopharma) resulted in hepatotoxicity requiring a liver transplant. Due to concerns about hepatotoxicity, this specific extract was removed from the market by the manufacturer (14310). Since then, at least 5 cases of liver toxicity necessitating liver transplantation have been reported for patients who used green tea extracts (94898,107158). In another case, use of green tea (Applied Nutrition Green Tea Fat Burner) in combination with whey protein, a nutritional supplement (GNC Mega Men Sport), and prickly pear cactus resulted in acute liver failure (90162).
Despite the numerous reports of hepatotoxicity associated with the use of green tea products, the actual number of hepatotoxicity cases is low when the prevalence of green tea use is considered. From 2006 to 2016, liver injury from green tea products was estimated have occurred in only 1 out of 2.7 million patients who used green tea products (94897,95440).
In addition to the fact that green tea hepatotoxicity is uncommon, it is also not clear which patients are most likely to experience liver injury (94897,95440). The hepatotoxicity does not appear to be an allergic reaction or an autoimmune reaction (94897). It is possible that certain extraction processes, for example, ethanolic extracts, produce hepatotoxic constituents. However, in most cases, the presence of contaminants in green tea products has not been confirmed in laboratory analyses (90162).
Although results from one analysis of 4 small clinical studies disagrees (94899), most analyses of clinical data, including one conducted by the European Food Safety Association, found that hepatotoxicity from green tea products is associated with the dose of EGCG in the green tea product. Results show that daily intake of EGCG in amounts greater than or equal to 800 mg per day is associated with a higher incidence of elevated liver enzymes such as alanine transaminase (ALT) (95440,95696,97131). However, it is still unclear what maximum daily dose of EGCG will not increase liver enzyme levels or what minimum daily dose of EGCG begins to cause liver injury. In many cases of liver injury, the dose of green tea extract and/or EGCG is not known. Therefore, a minimum level of green tea extract or EGCG that would cause liver injury in humans cannot be determined (102722). Keep in mind that daily intake of green tea infusions provides only 90-300 mg of EGCG daily. So for a majority of people, green tea infusions are likely safe and unlikely to cause liver injury (95696). Also, plasma levels of EGCG are increased when green tea catechins are taken in the fasting state, suggesting that green tea extract should be taken with food (102722).
Until more is known, advise patients that green tea products, especially those containing green tea extract, might cause liver damage. However, let them know that the risk is uncommon, and it is not clear which products are most likely to cause the adverse effect or which patients are most likely to be affected. Advise patients with liver disease to consult their healthcare provider before taking products with green tea extract and to notify their healthcare provider if they experience symptoms of liver damage, including jaundice, dark urine, sweating, or abdominal pain (102722).
Immunologic ...Orally, matcha tea has resulted in at least one case of anaphylaxis related to green tea proteins. A 9-year-old male experienced systemic redness and hives, nausea, and anaphylaxis 60 minutes after consuming matcha tea-flavored ice cream (107169). The caffeine found in green tea can also cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).
Musculoskeletal
...Orally, the ingestion of the green tea constituent epigallocatechin gallate (EGCG) or a decaffeinated green tea polyphenol mixture may cause mild muscle pain (36398).
There is some concern regarding the association between caffeinated green tea products and osteoporosis. Epidemiological evidence regarding the relationship between caffeinated beverages such as green tea and the risk for osteoporosis is contradictory. Caffeine can increase urinary excretion of calcium (2669,10202,11317). Females with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake of less than 400 mg per day, or about 8 cups of green tea, doesn't seem to significantly increase osteoporosis risk in most postmenopausal adults with normal calcium intake (2669,6025,10202,11317).
Neurologic/CNS
...Orally, green tea can cause central nervous system stimulation and adverse effects such as headache, anxiety, dizziness, insomnia, fatigue, agitation, tremors, restlessness, and confusion.
These effects are more common with higher doses of green tea or green tea extract, equivalent to 5-6 liters of tea per day (8117,11366,53719,90139,102716). The green tea constituent epigallocatechin gallate (EGCG) or decaffeinated green tea may also cause mild dizziness and headache (36398).
Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, temporary loss of consciousness, and hospitalization requiring life support has been associated with the combined use of ephedra and caffeine (2729).
Topically, green tea extract (Polyphenon E ointment) may cause headache when applied to the genital area (36442).
Psychiatric ...Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, and psychological dependence (11832). The existence or clinical importance of caffeine withdrawal is controversial. Some researchers think that if it exists, it appears to be of little clinical significance (11839). Other researchers suggest symptoms such as headache; tiredness and fatigue; decreased energy, alertness, and attentiveness; drowsiness; decreased contentedness; depressed mood; difficulty concentrating; irritability; and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms such as delirium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains, and flushed face have been described. However, these symptoms may be from nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).
Pulmonary/Respiratory ...A case of granulomatous alveolitis with lymph follicles has been reported for a 67-year-old female who used green tea infusions to wash her nasal cavities for 15 years (54088). Her symptoms disappeared 2 months after stopping this practice and following an undetermined course of corticosteroids. In a case report, hypersensitivity pneumonitis was associated with inhalation of catechin-rich green tea extracts (54025). Occupational exposure to green tea dust can cause sensitization, which may include nasal and asthmatic symptoms (11365).
Renal ...There are two cases of hypokalemia associated with drinking approximately 8 cups daily of green tea in an elderly couple of Asian descent. The hypokalemia improved after reducing their intake by 50%. It is possible that this was related to the caffeine in the green tea (98418).
Other ...Orally, intake of a specific green tea extract product (Polyphenon E) may cause weight gain (90139).
General ...Topically, jasmine may cause allergic contact dermatitis, delayed-type hypersensitivity, and type 1 hypersensitivity (56955,57027,57032,98684).
Immunologic ...Topically, jasmine essential oil and jasmine flower can cause allergic contact dermatitis (56955,57027,57032). Among patients who are sensitive to fragrance materials, jasmine may cause delayed-type hypersensitivity. The reported prevalence of this type of reaction ranges from 0.4% to 1.6% (89684). One case of type 1 hypersensitivity to jasmine has also been reported. The patient experienced chest tightness, wheezing, itchy skin, and macular erythematous eruption within minutes of exposure to jasmine. The eruption subsided within 20 minutes of moving away from the plant. An immunoblotting assay revealed IgE reactivity (98684).
General ...No adverse effects have been reported. However, a high-quality assessment of safety has not been conducted.
General
...Orally, peony seems to be well tolerated when used alone and as part of Chinese herbal formulas.
Most Common Adverse Effects:
Orally: Abdominal distension, anorexia, diarrhea, gastrointestinal discomfort, nausea.
Topically: Dermatitis.
Dermatologic ...Topically, peony has been reported to cause contact dermatitis (13555).
Endocrine ...Orally, a specific traditional Chinese medicine preparation called DDT has been reported to lower follicle-stimulating hormone (FSH) levels and increase estradiol levels. It is not known if this effect is due to peony or the other ingredients (48404). Another specific traditional Chinese medicine preparation, Toki-shakuyaku-san, has been reported to increase plasma progesterone levels in some patients. It is not known if this effect is due to peony or the other ingredients (15294).
Gastrointestinal ...Orally, peony and total glucosides of peony (TGP) have been reported to cause gastrointestinal discomfort, including abdominal distension, anorexia, diarrhea, and nausea, in some patients (13538,92785,97949,98466,100992). In one clinical study, diarrhea was reported in 5% of patients taking TGP 600 mg three times daily for 24 weeks versus 1% of patients taking placebo (100992).
Hematologic ...Orally, there is one case report of easy gum bleeding, epistaxis, and skin bruising with an international normalized ratio (INR) above 6 in a 61-year-old male who was previously stable on warfarin therapy. This patient had switched from one brand of quilinggao, a popular Chinese herbal product, to another brand 5 days prior. This product contained Fritillaria spp. (beimu), Paeonia rubra, Chinese peony (chishao), Lonicera japonica (jinyinhua), and Poncirus trifoliata (jishi). The patient's INR decreased to 1.9 after temporary withdrawal of warfarin therapy. Upon re-initiation of quilinggao, his INR increased to 5.2. It is not known if the increased INR is due to peony or the other ingredients (68343).
General
...Orally, schisandra seems to be generally well tolerated.
Most Common Adverse Effects:
Orally: Decreased appetite, heartburn, stomach upset, and urticaria.
Dermatologic ...Orally, schisandra can cause urticaria in some patients (11).
Gastrointestinal ...Orally, schisandra can cause heartburn, decreased appetite, and stomach upset (11).
