Vitamin C (as ascorbic acid) • Vitamin B6 (as pyridoxine HCl) • Vitamin B12 (as cyanocobalamin) • Eleuthero root (eleutherococcus senticosus) • Chamomile flowers (matricaria recutita) • Tilia Estrella flowers (ternstroemia pringler) • Lemon Verbena leaves (aloysia citriodora). Other Ingredients: Peppermint, Cinnamon, West Indian Lemon Grass, Natural Lemon Flavor with Other Natural Flavors (contains soy lecithin), Ginger, Licorice, Catnip, Roasted Chicory.
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 Tension Tamer Extra 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
Below is general information about the safety of the known ingredients contained in the product Tension Tamer Extra 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.
LIKELY SAFE ...when used orally and appropriately, short-term. Eleuthero root extract 300-2000 mg has been used safely in clinical trials lasting up to 3 months (730,1427,2574,7522,11099,15586,91509). There is insufficient reliable information available about the safety of eleuthero when used long-term.
CHILDREN: POSSIBLY SAFE
when used orally in adolescents aged 12-17 years, short-term.
Eleuthero 750 mg three times daily was used for 6 weeks with apparent safety in one clinical trial (75028). There is insufficient reliable information available about the safety of eleuthero in children or adolescents when used long-term.
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.
LIKELY SAFE ...when used orally in amounts commonly found in foods. German chamomile has Generally Recognized as Safe (GRAS) status in the US (4912,110318).
POSSIBLY SAFE ...when used orally, for medicinal purposes, short-term. German chamomile has been used with apparent safety at doses of up to 1500 mg daily for up to 26 weeks (6655,12724,12729,13089,19377,19716,104806,111380). ...when applied topically. A lotion containing 0.2% microencapsulated German chamomile extract has been applied to the skin with apparent safety for up to 35 days (108993). ...when used topically as an oral rinse (99853).
CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term.
Preliminary clinical research suggests that several multi-ingredient products containing German chamomile are safe in infants when used for up to 4 weeks (16735,19705,19715,96278). ...when used topically and appropriately, short-term. Six drops of oil infused with German chamomile flower has been applied nightly with apparent safety for up to 6 weeks in children 6-18 years old (98621).
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.
LIKELY SAFE ...when used orally in amounts commonly found in foods. Lemon verbena has Generally Recognized as Safe (GRAS) status in the US (4912).
POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts, short-term. The leaf extract has been used with apparent safety at a dose of 400 mg daily for up to 8 weeks (97288,109669). The leaf essential oil has been used with apparent safety in doses of 1.66 mg daily for 4 weeks (104202). There is insufficient reliable information available about the safety of lemon verbena when used topically.
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.
LIKELY SAFE ...when used orally, topically, intravenously, intramuscularly, or intranasally and appropriately. Vitamin B12 is generally considered safe, even in large doses (15,1344,1345,1346,1347,1348,2909,6243,7289,7881)(9414,9416,10126,14392,15765,82832,82949,82860,82864,90386)(111334,111551).
PREGNANCY: LIKELY SAFE
when used orally in amounts that do not exceed the recommended dietary allowance (RDA).
The RDA for vitamin B12 during pregnancy is 2.6 mcg daily (6243). There is insufficient reliable information available about the safety of larger amounts of vitamin B12 during pregnancy.
LACTATION: LIKELY SAFE
when used orally in amounts that do not exceed the recommended dietary allowance (RDA).
The RDA of vitamin B12 during lactation is 2.8 mcg daily (6243). There is insufficient reliable information available about the safety of larger amounts of vitamin B12 while breastfeeding.
LIKELY SAFE ...when used orally and appropriately in doses that do not exceed the tolerable upper intake level (UL) of 100 mg daily for adults (15). ...when used parenterally and appropriately. Injectable vitamin B6 (pyridoxine) is an FDA-approved prescription product (15).
POSSIBLY SAFE ...when used orally and appropriately in doses of 101-200 mg daily (6243,8558).
POSSIBLY UNSAFE ...when used orally in doses at or above 500 mg daily. High doses, especially those exceeding 1000 mg daily or total doses of 1000 grams or more, pose the most risk. However, neuropathy can occur with lower daily or total doses (6243,8195). ...when used intramuscularly in high doses and frequency due to potential for rhabdomyolysis (90795).
CHILDREN: LIKELY SAFE
when used orally and appropriately (3094).
CHILDREN: POSSIBLY SAFE
when used orally and appropriately in amounts exceeding the recommended dietary allowance (5049,8579,107124,107125,107135).
CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses, long-term (3094).
PREGNANCY: LIKELY SAFE
when used orally and appropriately.
A special sustained-release product providing vitamin B6 (pyridoxine) 75 mg daily is FDA-approved for use in pregnancy. Vitamin B6 (pyridoxine) is also considered a first-line treatment for nausea and vomiting in pregnancy by the American College of Obstetrics and Gynecology (111601). However, it should not be used long-term or without medical supervision and close monitoring.
PREGNANCY: POSSIBLY UNSAFE
when used orally in excessive doses.
There is some concern that high-dose maternal vitamin B6 (pyridoxine) can cause neonatal seizures (4609,6397,8197).
LACTATION: LIKELY SAFE
when used orally in doses not exceeding the recommended dietary allowance (RDA) (3094).
The RDA in lactating women is 2 mg daily. There is insufficient reliable information available about the safety of vitamin B6 when used in higher doses in breast-feeding women.
LIKELY SAFE ...when used orally, topically, intramuscularly, or intravenously and appropriately. Vitamin C is safe when taken orally in doses below the tolerable upper intake level (UL). Tell patients not to exceed the UL of 2000 mg daily (1959,4713,4714,4844). ...when used intravenously or intramuscularly and appropriately. Injectable vitamin C is an FDA-approved prescription product (15).
POSSIBLY UNSAFE ...when used orally in excessive doses. Doses greater than the tolerable upper intake level (UL) of 2000 mg daily can significantly increase the risk of adverse effects such as osmotic diarrhea and gastrointestinal upset (4844).
CHILDREN: LIKELY SAFE
when used orally and appropriately (4844,10352,14443).
CHILDREN: POSSIBLY UNSAFE
when used orally in excessive amounts.
Tell patients not to use doses above the tolerable upper intake level (UL) of 400 mg daily for children ages 1 to 3 years, 650 mg daily for children 4 to 8 years, 1200 mg daily for children 9 to 13 years, and 1800 mg daily for adolescents 14 to 18 years. Higher doses can cause osmotic diarrhea and gastrointestinal upset (4844).
PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (4844).
PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses.
Tell patients over age 19 not to use doses exceeding the UL of 2000 mg daily when pregnant or breast-feeding and for those 14-18 years of age not to use doses exceeding 1800 mg daily when pregnant or breast-feeding. Higher doses can cause osmotic diarrhea and gastrointestinal upset. Large doses of vitamin C during pregnancy can also cause newborn scurvy (4844); avoid using.
Below is general information about the interactions of the known ingredients contained in the product Tension Tamer Extra 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, eleuthero may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
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Theoretically, eleuthero might have additive effects when used with antidiabetes drugs.
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Animal research suggests that certain constituents of eleuthero have hypoglycemic activity in both healthy and diabetic animals (7591,73535,74932,74956,74988,74990). A small study in adults with type 2 diabetes also shows that taking eleuthero for 3 months can lower blood glucose levels (91509). However, one very small study in healthy individuals shows that taking powdered eleuthero 3 grams, 40 minutes prior to a 75-gram oral glucose tolerance test, significantly increases postprandial blood glucose levels when compared with placebo (12536). These contradictory findings might be due to patient-specific variability and variability in active ingredient ratios.
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Theoretically, eleuthero might increase levels of drugs metabolized by CYP1A2.
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In vitro and animal research suggest that standardized extracts of eleuthero inhibit CYP1A2 (7532). This effect has not been reported in humans.
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Theoretically, eleuthero might increase levels of drugs metabolized by CYP2C9.
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In vitro and animal research suggest that standardized extracts of eleuthero might inhibit CYP2C9 (7532). This effect has not been reported in humans.
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Theoretically, eleuthero might increase levels of drugs metabolized by CYP2D6.
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Theoretically, eleuthero might increase levels of drugs metabolized by CYP3A4.
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Eleuthero might increase serum digoxin levels and increase the risk of side effects.
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In one case report, a 74-year-old male who was stabilized on digoxin presented with an elevated serum digoxin level after starting an eleuthero supplement, without symptoms of toxicity. After stopping the supplement, serum digoxin levels returned to normal (543). It is not clear whether this was due to a pharmacokinetic interaction or to interference with the digoxin assay (15585). Although the product was found to be free of digoxin and digitoxin (543), it was not tested for other contaminants (797).
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Theoretically, eleuthero might interfere with immunosuppressive drugs because of its immunostimulant activity.
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Theoretically, eleuthero might decrease levels of drugs metabolized by OATP.
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In vitro research suggests that eleuthero inhibits OATP2B1, which might reduce the bioavailability of oral drugs that are substrates of OATP2B1 (35450). Due to the weak inhibitory effect identified in this study, this interaction is not likely to be clinically significant.
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Theoretically, eleuthero might increase levels of P-glycoprotein substrates.
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Theoretically, German chamomile might have additive effects when used with CNS depressants.
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Theoretically, large amounts of German chamomile might reduce the effectiveness of oral contraceptives.
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In vitro, German chamomile has demonstrated antiestrogenic activity (12728). Theoretically, concomitant use of large amounts of German chamomile might interfere with contraceptive drugs through competition for estrogen receptors.
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Theoretically, German chamomile might inhibit CYP1A2 and increase levels of drugs metabolized by these enzymes.
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Theoretically, German chamomile might inhibit CYP2C9 and increase levels of drugs metabolized by these enzymes.
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In vitro evidence shows that German chamomile might inhibit CYP2C9 (19720). So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP2C9 in patients taking German chamomile.
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Theoretically, German chamomile might inhibit CYP2D6 and increase levels of drugs metabolized by these enzymes.
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In vitro evidence shows that German chamomile might inhibit CYP2D6 (19720). So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP2D6 in patients taking German chamomile.
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Theoretically, German chamomile might inhibit CYP3A4 and increase levels of drugs metabolized by these enzymes.
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Theoretically, large amounts of German chamomile might reduce the effectiveness of estrogens.
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In vitro, German chamomile has demonstrated antiestrogenic activity (12728). Theoretically, large amounts of German chamomile might interfere with hormone replacement therapy through competition for estrogen receptors.
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Theoretically, large amounts of German chamomile might interfere with the activity of tamoxifen.
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In vitro, German chamomile has demonstrated antiestrogenic activity (12728).
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German chamomile might increase the effects of warfarin and increase the risk of bleeding.
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In one case, a 70-year-old female taking warfarin developed retroperitoneal hematoma and bilateral recti muscle bleeding along with an INR of 7.9 following ingestion of German chamomile tea 4-5 cups daily and use of a topical chamomile-based lotion applied 4-5 times daily (14309).
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Theoretically, taking lemon verbena with benzodiazepines might increase the risk of sedation and respiratory depression.
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Animal research shows that lemon verbena has additive sedative effects in mice that also received diazepam (104202).
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Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.
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Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.
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Research in hypertensive rats shows that vitamin B6 can decrease systolic blood pressure (30859,82959,83093). Similarly, clinical research in patients with hypertension shows that taking high doses of vitamin B6 may reduce systolic and diastolic blood pressure, possibly by reducing plasma levels of epinephrine and norepinephrine (83091).
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Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.
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Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people (3046).
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High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.
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High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.
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High-dose vitamin C might slightly prolong the clearance of acetaminophen.
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A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases (6451). This effect is not likely to be clinically significant.
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Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
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The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa (391). In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.
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Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
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Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption (10549,10550,10551,21556). In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely (10549). Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.
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Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
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The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin (391). In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.
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Acidification of the urine by vitamin C might increase aspirin levels.
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It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046). However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction is not clinically significant.
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Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
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It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046,4531). However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction probably is not clinically significant.
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Vitamin C might increase blood levels of estrogens.
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Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products (129,130,11161). It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall (129,11161). When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements (11161). Monitor these patients for estrogen-related side effects.
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Theoretically, vitamin C might decrease levels of fluphenazine.
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In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started (11017). The mechanism is not known, and there is no further data to confirm this interaction.
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Vitamin C can modestly reduce indinavir levels.
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One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown (11300,93578).
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Vitamin C can increase levothyroxine absorption.
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Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH (102978).
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Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
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A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease (7388,11537). It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.
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Acidification of the urine by vitamin C might increase salsalate levels.
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It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046). However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction probably is not clinically significant.
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High-dose vitamin C might reduce the levels and effectiveness of warfarin.
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Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption (11566). There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time (9804,9806). Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant (9805,9806,11566,11567). However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR) (90942). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.
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Below is general information about the adverse effects of the known ingredients contained in the product Tension Tamer Extra 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, eleuthero root is generally well tolerated when used short-term.
Most Common Adverse Effects:
Orally: Diarrhea, dyspepsia, gastrointestinal upset, headache, nausea, and urticaria.
Cardiovascular ...Orally, increased blood pressure has been reported in children with hypotension taking eleuthero in one clinical study (74980). Eleuthero has been reported to cause tachycardia, hypertension, and pericardial pain in patients with rheumatic heart disease or atherosclerosis. It is unclear if these effects were caused by eleuthero, or by the cardioglycoside-containing herb, silk vine (Periploca sepium), which is a common adulterant found in eleuthero products (12,797,6500).
Dermatologic ...Orally, eleuthero has been reported to cause rash in some clinical studies (75013,75028).
Gastrointestinal ...Orally, eleuthero has been reported to cause dyspepsia, nausea, diarrhea, and gastrointestinal upset in some patients (74938,75028,91510).
Genitourinary ...Orally, mastalgia and uterine bleeding were reported in 7. 3% of females taking eleuthero 2 grams daily in one clinical study (6500,11099). These adverse effects seem to be more likely with higher doses.
Neurologic/CNS
...Orally, headaches have been reported in 9.
8% of people taking eleuthero in one clinical study (11099).
In one case report, a 53-year-old female developed spontaneous subarachnoid hemorrhage associated with the use of an herbal supplement containing red clover, dong quai, and eleuthero (70419). It is unclear if this event was related to the use of eleuthero, the other ingredients, the combination, or another cause entirely.
Psychiatric ...Orally, nervousness has been reported in 7. 3% of people taking eleuthero in one clinical study (11099). Eleuthero has also been reported to cause slight anxiety, irritability, and melancholy in some patients (6500,11099). These adverse effects seem to be more likely to occur with higher doses.
General
...Orally and topically, German chamomile is well tolerated.
Most Common Adverse Effects:
Orally and topically: Allergic reactions and irritation.
Dermatologic ...Topically, German chamomile may cause allergic dermatitis and eczema (9766,9768,10377,110318).
Gastrointestinal ...When used topically as an oral rinse, German chamomile has been reported to cause nausea and burning in the mouth in some patients (99853).
Immunologic ...Orally, German chamomile tea can cause allergic reactions including severe hypersensitivity reactions and anaphylaxis in some patients (567). In one case report, a 47-year-old female who tolerated drinking chamomile tea, reported sneezing, nasal and ocular itching, red and watery eyes, and severe rhinorrhea after 10 years of occupational exposure to German chamomile dust (90542).
Ocular/Otic ...If used near the eyes, German chamomile can cause irritation (10377).
General
...Orally and topically, the extract and essential oil of lemon verbena leaf seems to be well tolerated.
Most Common Adverse Effects:
Topically: Contact dermatitis.
Dermatologic ...Contact dermatitis may occur with topical application of lemon verbena (6).
Renal ...Orally, lemon verbena oil may irritate the kidneys upon urinary excretion (4).
General
...Orally, intramuscularly, and topically, vitamin B12 is generally well-tolerated.
Most Common Adverse Effects:
Intramuscular: Injection site reactions.
Serious Adverse Effects (Rare):
Intramuscularly: Severe hypokalemia has been rarely linked with correction of megaloblastic anemia with vitamin B12.
Cardiovascular ...In human clinical research, an intravenous loading dose of folic acid, vitamin B6, and vitamin B12, followed by daily oral administration after coronary stenting, increased restenosis rates (12150). Hypertension following intravenous administration of hydroxocobalamin has been reported in human research (82870,82864).
Dermatologic
...Orally or intramuscularly, vitamin B12 can cause allergic reactions such as rash, pruritus, erythema, and urticaria.
Theoretically, allergic reactions might be caused by the cobalt within the vitamin B12 molecule (82864,90373,90381,103974). In one case report, oral methylcobalamin resulted in contact dermatitis in a 59-year-old Japanese female with a cobalt allergy (103974). In another case report, a 69-year-old female developed a symmetrical erythematous-squamous rash for 5 years after oral vitamin B12 supplementation for 10 years. A patch test confirmed that the systemic allergic dermatitis was due to vitamin B12 supplementation, which resolved 3 months after discontinuation (114578).
Vitamin B12 (intramuscular or oral) has also been associated with at least 19 cases of acneiform eruptions which resolved upon discontinuation of vitamin B12 (90365,90369,90388). High-dose vitamin B12 (20 mcg daily) and vitamin B6 (80 mg daily) have been associated with cases of rosacea fulminans characterized by intense erythema with nodules, papules, and pustules. Symptoms may last up to four months after the supplement is stopped and can be treated with systemic corticosteroids and topical therapy (10998,82870,82871).
Gastrointestinal ...Intravenously, vitamin B12 (hydroxocobalamin) 2. 5-10 grams can cause nausea and dysphagia (82864).
Genitourinary ...Intravenously, vitamin B12 (hydroxocobalamin) 5-15 grams has been associated with chromaturia in clinical research (82870,82871,112282,112264).
Hematologic ...According to case report data, the correction of megaloblastic anemia with vitamin B12 may result in fatal hypokalemia (82914).
Musculoskeletal ...According to case report data, correction of megaloblastic anemia with vitamin B12 has precipitated gout in susceptible individuals (82879).
Neurologic/CNS ...Treatment with vitamin B12 has been rarely associated with involuntary movements in infants with vitamin B12 deficiency (90370,90385,90397). In some cases these adverse reactions were misdiagnosed as seizures or infantile tremor syndrome (90370,90385). These adverse reactions presented 2-5 days after treatment with vitamin B12 and resolved once vitamin B12 was discontinued (90370,90385,90397).
Oncologic ...Although some epidemiological research disagrees (9454), most research has found that elevated plasma levels of vitamin B12 are associated with an increased risk of various types of cancer, including lung and prostate cancers and solid tumors (50411,102383,107743). One study found, when compared with blood levels of vitamin B12 less than 1000 ng/mL, plasma vitamin B12 levels of at least 1000 ng/mL was strongly associated with the occurrence of solid cancer (107743). It is unclear if increased intake of vitamin B12, either through the diet or supplementation, directly affects the risk of cancer. It is possible that having cancer increases the risk of vitamin B12 elevation. However, one observational study has found that the highest quintile of dietary intake of vitamin B12 is associated with a 75% increased incidence of developing esophageal cancer when compared with the lowest quintile in never drinkers, but not drinkers (107147).
Renal ...There is a case report of oxalate nephropathy in a 54-year-old male which was determined to be related to the use of intravenous hydroxocobalamin as treatment for cyanide poisoning. Intermittent hemodialysis was started 5 days after admission, along with a low-oxalate diet, oral calcium acetate, and pyridoxine 5 mg/kg daily (107148). A review of the use of intravenous hydroxocobalamin for suspected cyanide poisoning in 21 intensive care units in France between 2011 and 2017 resulted in a 60% increased odds of acute kidney injury and a 77% increased odds of severe acute kidney injury in the first week. However, biopsies were not conducted and a direct link with use of hydroxocobalamin could not be made (107139).
Other ...Several studies have found that higher vitamin B12 levels may be associated with increased mortality or decreased survival rates in hospitalized elderly patients (82889,82812,82857,82895). Human research has also found a positive correlation between vitamin B12 status and all-cause mortality in Pima Indians with diabetes (82863).
General
...Orally or by injection, vitamin B6 is well tolerated in doses less than 100 mg daily.
Most Common Adverse Effects:
Orally or by injection: Abdominal pain, allergic reactions, headache, heartburn, loss of appetite, nausea, somnolence, vomiting.
Serious Adverse Effects (Rare):
Orally or by injection: Sensory neuropathy (high doses).
Dermatologic ...Orally, vitamin B6 (pyridoxine) has been linked to reports of skin and other allergic reactions and photosensitivity (8195,9479,90375). High-dose vitamin B6 (80 mg daily as pyridoxine) and vitamin B12 (20 mcg daily) have been associated with cases of rosacea fulminans characterized by intense erythema with nodules, papules, and pustules. Symptoms may persist for up to 4 months after the supplement is stopped, and may require treatment with systemic corticosteroids and topical therapy (10998).
Gastrointestinal ...Orally or by injection, vitamin B6 (pyridoxine) can cause nausea, vomiting, heartburn, abdominal pain, mild diarrhea, and loss of appetite (8195,9479,16306,83064,83103,107124,107127,107135). In a clinical trial, one patient experienced infectious gastroenteritis that was deemed possibly related to taking vitamin B6 (pyridoxine) orally up to 20 mg/kg daily (90796). One small case-control study has raised concern that long-term dietary vitamin B6 intake in amounts ranging from 3.56-6.59 mg daily can increase the risk of ulcerative colitis (3350).
Hematologic ...Orally or by injection, vitamin B6 (pyridoxine) can cause decreased serum folic acid concentrations (8195,9479). One case of persistent bleeding of unknown origin has been reported in a clinical trial for a patient who used vitamin B6 (pyridoxine) 100 mg twice daily on days 16 to 35 of the menstrual cycle (83103). It is unclear if this effect was due to vitamin B6 intake.
Musculoskeletal ...Orally or by injection, vitamin B6 (pyridoxine) can cause breast soreness or enlargement (8195).
Neurologic/CNS ...Orally or by injection, vitamin B6 (pyridoxine) can cause headache, paresthesia, and somnolence (8195,9479,16306). Vitamin B6 (pyridoxine) can also cause sensory neuropathy, which is related to daily dose and duration of intake. Doses exceeding 1000 mg daily or total doses of 1000 grams or more pose the most risk, although neuropathy can occur with lower daily or total doses as well (8195). The mechanism of the neurotoxicity is unknown, but is thought to occur when the liver's capacity to phosphorylate pyridoxine via the active coenzyme pyridoxal phosphate is exceeded (8204). Some researchers recommend taking vitamin B6 as pyridoxal phosphate to avoid pyridoxine neuropathy, but its safety is unknown (8204). Vitamin B6 (pyridoxine) neuropathy is characterized by numbness and impairment of the sense of position and vibration of the distal limbs, and a gradual progressive sensory ataxia (8196,10439). The syndrome is usually reversible with discontinuation of pyridoxine at the first appearance of neurologic symptoms. Residual symptoms have been reported in patients taking more than 2 grams daily for extended periods (8195,8196). Tell patients daily doses of 100 mg or less are unlikely to cause problems (3094).
Oncologic ...In females, population research has found that a median intake of vitamin B6 1. 63 mg daily is associated with a 3.6-fold increased risk of rectal cancer when compared with a median intake of 1.05 mg daily (83024). A post-hoc subgroup analysis of results from clinical research in adults with a history of recent stroke or ischemic attack suggests that taking folic acid, vitamin B12, and vitamin B6 does not increase cancer risk overall, although it was associated with an increased risk of cancer in patients who also had diabetes (90378). Also, in patients with nasopharyngeal carcinoma, population research has found that consuming at least 8.6 mg daily of supplemental vitamin B6 during treatment was associated with a lower overall survival rate over 5 years, as well as a reduced progression-free survival, when compared with non-users and those with intakes of up to 8.6 mg daily (107134).
General
...Orally, intravenously, and topically, vitamin C is well-tolerated.
Most Common Adverse Effects:
Orally: Abdominal cramps, esophagitis, heartburn, headache, osmotic diarrhea, nausea, vomiting. Kidney stones have been reported in those prone to kidney stones. Adverse effects are more likely to occur at doses above the tolerable upper intake level of 2 grams daily.
Topically: Irritation and tingling.
Serious Adverse Effects (Rare):
Orally: There have been rare case reports of carotid inner wall thickening after large doses of vitamin C.
Intravenously: There have been case reports of hyperoxalosis and oxalate nephropathy following high-dose infusions of vitamin C.
Cardiovascular
...Evidence from population research has found that high doses of supplemental vitamin C might not be safe for some people.
In postmenopausal adults with diabetes, supplemental vitamin C intake in doses greater than 300 mg per day is associated with increased risk of cardiovascular mortality. However, dietary intake of vitamin C is not associated with this risk. Also, vitamin C intake is not associated with an increased risk of cardiovascular mortality in patients without diabetes (12498).
Oral supplementation with vitamin C has also been associated with an increased rate of carotid inner wall thickening in men. There is preliminary evidence that supplemental intake of vitamin C 500 mg daily for 18 months can cause a 2.5-fold increased rate of carotid inner wall thickening in non-smoking men and a 5-fold increased rate in men who smoked. The men in this study were 40-60 years old (1355). This effect was not associated with vitamin C from dietary sources (1355).
There is also some concern that vitamin C may increase the risk of hypertension in some patients. A meta-analysis of clinical research suggests that, in pregnant patients at risk of pre-eclampsia, oral intake of vitamin C along with vitamin E increases the risk of gestational hypertension (83450). Other clinical research shows that oral intake of vitamin C along with grape seed polyphenols can increase both systolic and diastolic blood pressure in hypertensive patients (13162).
Dental ...Orally, vitamin C, particularly chewable tablets, has been associated with dental erosion (83484).
Dermatologic ...Topically, vitamin C might cause tingling or irritation at the site of application (6166). A liquid containing vitamin C 20%, red raspberry leaf cell culture extract 0.0005%, and vitamin E 1% (Antioxidant and Collagen Booster Serum, Max Biocare Pty Ltd.) has been reported to cause mild tingling and skin tightness (102355). It is unclear if these effects are due to vitamin C, the other ingredients, or the combination.
Gastrointestinal ...Orally, the adverse effects of vitamin C are dose-related and include nausea, vomiting, esophagitis, heartburn, abdominal cramps, gastrointestinal obstruction, and diarrhea. Doses greater than the tolerable upper intake level (UL) of 2000 mg per day can increase the risk of adverse effects such as osmotic diarrhea and severe gastrointestinal upset (3042,4844,96707,104450). Mineral forms of vitamin C, such as calcium ascorbate (Ester-C), seem to cause fewer gastrointestinal adverse effects than regular vitamin C (83358). In a case report, high dose intravenous vitamin C was associated with increased thirst (96709).
Genitourinary ...Orally, vitamin C may cause precipitation of urate, oxalate, or cysteine stones or drugs in the urinary tract (10356). Hyperoxaluria, hyperuricosuria, hematuria, and crystalluria have occurred in people taking 1 gram or more per day (3042,90943). Supplemental vitamin C over 250 mg daily has been associated with higher risk for kidney stones in males. There was no clear association found in females, but the analysis might not have been adequately powered to evaluate this outcome (104029). In people with a history of oxalate kidney stones, supplemental vitamin C 1 gram per day appears to increase kidney stone risk by 40% (12653). A case of hematuria, high urine oxalate excretion, and the presence of a ureteral stone has been reported for a 9-year-old male who had taken about 3 grams of vitamin C daily since 3 years of age. The condition resolved with cessation of vitamin C intake (90936).
Hematologic ...Prolonged use of large amounts of vitamin C can result in increased metabolism of vitamin C; subsequent reduction in vitamin C intake may precipitate the development of scurvy (15). In one case, a patient with septic shock and a large intraperitoneal hematoma developed moderate hemolysis and increased methemoglobin 12 hours after a high-dose vitamin C infusion. The patient received a blood transfusion and the hemolysis resolved spontaneously over 48 hours (112479).
Neurologic/CNS ...Orally, the adverse effects of vitamin C are dose-related and include fatigue, headache, insomnia, and sleepiness (3042,4844,83475,83476).
Renal ...Hyperoxalosis and oxalate nephropathy have been reported following high-dose infusions of vitamin C. Hyperoxalosis and acute kidney failure contributed to the death of a 76-year-old patient with metastatic adenocarcinoma of the lung who received 10 courses of intravenous infusions containing vitamins, including vitamin C and other supplements over a period of 1 month. Dosages of vitamin C were not specified but were presumed to be high-dose (106618). In another case, a 34-year-old patient with a history of kidney transplant and cerebral palsy was found unresponsive during outpatient treatment for a respiratory tract infection. The patient was intubated for acute hypoxemic respiratory failure, initiated on vasopressors, hydrocortisone, and antibacterial therapy, and received 16 doses of vitamin C 1.5 grams. Serum creatinine level peaked at greater than 3 times baseline and the patient required hemodialysis for oliguria and uncontrolled acidosis. Kidney biopsy revealed oxalate nephropathy with concomitant drug-induced interstitial nephritis (106625). In another case, a 41-year-old patient with a history of kidney transplant presented with fever, nausea, and decreased urine output 4 days after receiving intravenous vitamin C 7 grams for urothelial carcinoma. Serum creatinine levels increased from 1.7 mg/dL to 7.3 mg/dL over those 4 days, and hemodialysis was initiated 3 days after admission due to anuria. Renal biopsy confirmed the diagnosis of acute oxalate nephropathy (109962).
Other ...Intravenously, hypernatremia and falsely elevated ketone levels is reported in a patient with septic shock and chronic kidney disease after a high-dose vitamin C infusion. The hypernatremia resolved over 24 hours after cessation of the infusion (112479).
