Forskolin by Nutrition Essentials

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Angina. Although there has been interest in using oral coleus for angina, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Asthma. It is unclear if inhaled forskolin, a constituent of coleus, is beneficial in patients with asthma. Details: A preliminary clinical trial in patients with asthma shows that a single-dose inhalation of the powdered coleus constituent, forskolin, 10 mg, from a Spinhaler inhaler increases forced expiratory volume in one second (FEV1) when compared to baseline (7281,44432). Another, low-quality, trial in patients with asthma found that using a specific forskolin product (Pro-longevity Forskolin, Life Extension Foundation Buyers Club, Fort Lauderdale, Florida, USA) providing forskolin 10 mg per day orally for 6 months did not improve lung function, but resulted in fewer asthma attacks when compared to two inhalations of sodium cromoglycate three times daily for 6 months (91889). However, another preliminary trial in adults and children with mild asthma shows that taking oral forskolin 10 mg taken daily for 2 months, neither reduced asthma attacks nor improved lung function when compared with beclomethasone inhalations or when compared to baseline (91883).
• Atopic dermatitis (eczema). Although there has been interest in using oral coleus for atopic dermatitis, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Cancer. Although there has been interest in using oral coleus for cancer, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Congestive heart failure (CHF). Although there has been interest in using intravenous forskolin, a constituent of coleus, for CHF, there is insufficient reliable information about the clinical effects of forskolin or coleus for this purpose.
• Dilated cardiomyopathy. It is unclear if intravenous forskolin, a constituent of coleus, is beneficial in patients with dilated cardiomyopathy. Details: Preliminary clinical research in patients with dilated cardiomyopathy shows that using intravenous coleus 0.5 mcg/kg/minute, titrated at 15 minute intervals to 3 mg/kg/minute, increases cardiac output and pulmonary vascular pressure when compared to baseline (7278). The validity of this study is limited by the lack of a comparator group.
• Dry eye. Oral coleus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with dry eyes shows that taking a specific combination supplement (Kronek, SOOFT Italia, Montegiorgio, Italy) containing an extract of Coleus forskolii 150 mg (10% forskolin), rutin 200 mg, thiamine 0.7 mg, and riboflavin 0.8 mg, 2 capsules by mouth daily for 30 days moderately decreases dry eye symptoms when compared with placebo (91888). It is unclear if this benefit is due to coleus, other ingredients, or the combination.
• Dysmenorrhea. Although there has been interest in using oral coleus for dysmenorrhea, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Erectile dysfunction (ED). It is unclear if intracavernosal forskolin, a constituent of coleus, is beneficial in patients with ED. Details: Preliminary clinical evidence in males with ED treated with intracavernosal injections of phentolamine, papaverine, and prostaglandin E shows that intracavernosal forskolin, a constituent of coleus, 1 mg once daily improves penile rigidity scores and average erection duration when compared to no additional intervention (44441).
• Glaucoma. Oral coleus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking two tablets of a specific combination supplement (Kronek Sooft Italia SpA, Montegiorgio, Italy) containing forskolin 15 mg, rutin 200 mg, vitamin B1 1.5 mg, and vitamin B2 1.5 mg for 7 or 30 days prevents increases in intraocular pressure and decreases intraocular pressure by 10% when compared with placebo in glaucoma patients (91887,91890). Preliminary clinical research on another specific combination supplement (Gangliolife, SOOFT Italia), two tablets taken twice daily for 1 year in addition to standard topical therapy results in a decrease in intraocular pressure compared to standard therapy alone in patients with primary open angle glaucoma. One tablet of the supplement contains coleus extract 150 mg (standardized to 10% forskolin), homotaurine 100 mg, L- carnosine 50 mg, vitamin B1 1.1 mg, vitamin B2 1.4 mg, vitamin B6 1.4 mg, folic acid 0.2 mg, and magnesium 150 mg (91886).
• Hypertension. It is unclear if oral coleus is beneficial in patients with hypertension. Details: Preliminary clinical research shows that taking coleus root tuber 1 gram or coleus whole root 1.4 grams orally three times daily after food for 2 months modestly decreases blood pressure compared to baseline in elderly patients with hypertension (91884). The validity of this study is limited by the lack of a comparator group.
• Insomnia. Although there has been interest in using oral coleus for insomnia, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Irritable bowel syndrome (IBS). Although there has been interest in using oral coleus for irritable bowel syndrome, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Obesity. It is unclear if oral coleus is beneficial in patients with obesity. Details: Preliminary clinical research in overweight and obese males shows that taking a specific coleus supplement (Forslean, Sabina Corp., Piscataway, NJ) containing a 10% forskolin extract 250 mg twice daily for 12 weeks does not decrease body weight when compared with placebo. However, taking the supplement lowered body fat by 4% compared with 1% in placebo (91882). Another small clinical trial in overweight and obese patients following a calorie-restricted diet shows that taking a coleus extract capsule 250 mg twice daily before meals for 12 weeks does not reduce body weight when compared with placebo (91885).
• Psoriasis. Although there has been interest in using oral coleus for psoriasis, there is insufficient reliable information about the clinical effects of coleus for this purpose.
• Urinary tract infections (UTIs). Although there has been interest in using oral coleus for UTIs, there is insufficient reliable information about the clinical effects of coleus for this purpose. More evidence is needed to rate coleus for these uses.

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POSSIBLY SAFE ...when used orally and appropriately, short-term. Coleus extract 500 mg daily has been used for up to 3 months without significant adverse effects (91885,100851). ...when used intravenously and appropriately, short-term. Intravenous forskolin, a constituent of coleus, seems to be safe when given at an appropriate rate of 0.5 mcg/kg/minute and increased at 15 minute intervals to 1.0, 2.0, and 3.0 mcg/kg/minute up to 1 hour (7278,7279). ...when used by inhalation and appropriately. Single-dose inhalation of forskolin powder 10 mg from a Spinhaler inhalator seems to be safe and well-tolerated (7281). ...when used ophthalmologically and appropriately. Coleus suspension eye drops (1%) have been safely used in clinical studies (7282,7283,7284,7402,7403,7405).

POSSIBLY UNSAFE ...when used orally in higher doses. Although coleus extracts have been used with apparent safety in doses up to 1.4 grams daily for 2 months (91884), taking coleus extract in doses exceeding 500 mg daily has been associated with an increased incidence of adverse effects, which are primarily gastrointestinal (100851).

PREGNANCY: POSSIBLY UNSAFE
when used orally. Evidence from animal research suggests that high doses of coleus can inhibit embryo implantation and/or delay fetal development (25174); avoid using.

LACTATION:
Insufficient reliable information available; avoid using.

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of coleus and anticoagulant or antiplatelet drugs might increase the risk of bruising and bleeding.  Details In vitro and animal research shows that forskolin, a constituent of coleus, can inhibit platelet aggregation and adhesion (7410,7411,7412).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, combining coleus with antihypertensive drugs might cause additive blood pressure lowering effects and increase the risk of hypotension.  Details Animal research shows that forskolin, a constituent of coleus, may lower blood pressure (7278,7279,44424,44431).

CALCIUM CHANNEL BLOCKERS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Theoretically, combining coleus with calcium channel blockers might increase the coronary vasodilatory effects.  Details Forskolin, a constituent of coleus, and calcium channel blockers both cause coronary vasodilatory effects (7278,7279).

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking coleus may affect drugs metabolized by CYP2C9 and increase the risk of adverse effects or reduce the effectiveness.  Details Research on the effect of coleus on CYP2C9 is conflicting. Some animal research shows that coleus extract can induce CYP2C9, while in vitro research shows that coleus can inhibit CYP2C9 (91891). Until more is known, advise patients that taking coleus might increase or decrease levels of drugs metabolized by CYP2C9.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking coleus might decrease serum levels of drugs metabolized by CYP3A4.  Details In vitro research shows that coleus can activate the nuclear receptor, pregnane X receptor (PXR), which results in increased expression of CYP3A4 (44399,44412). Although the clinical significance of this is not known, use caution when considering concomitant use of coleus and other drugs affected by these enzymes.

NITRATES Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Theoretically, combining coleus with nitrates might increase the coronary vasodilatory effects.  Details Forskolin, a constituent of coleus, and nitrates both cause coronary vasodilatory effects (7278,7279,44424).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking coleus may affect the metabolism of warfarin and increase the risk of adverse effects or reduce the effectiveness.  Details Some animal research shows that coleus extract can induce cytochrome P450 2C9 (CYP2C9), an enzyme that metabolizes warfarin. However, other in vitro research shows that coleus can inhibit CYP2C9 (91891). Theoretically, taking coleus with drugs metabolized by CYP2C9 might affect drug levels and the risk of adverse effects. Until more is known, advise patients that taking coleus might increase or decrease levels of warfarin.

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General ...Orally, intravenously, ophthalmologically, and by inhalation, coleus seems to be well tolerated.
Most Common Adverse Effects:
Orally: Constipation, diarrhea, nausea, vomiting.
Intravenously: Flushing, hypotension, tachycardia.
Ophthalmologically: Conjunctival hyperemia, stinging eyes.
Inhalation: Irritation of the respiratory tract, restlessness, tremor.

Cardiovascular ...Intravenously, the coleus constituent, forskolin, can cause tachycardia, flushing and hypotension (7279,44424,44431).

Dermatologic ...Two cases of contact dermatitis have been reported following airborne exposure to coleus (44426,44418).

Gastrointestinal ...Orally, coleus can cause dose-related diarrhea and other gastrointestinal symptoms. Increased bowel movements and loose stools have been reported in 1 of 15 patients taking coleus extract in a clinical trial (91885). Some retrospective evidence reports about a 10% rate of gastrointestinal adverse effects from oral coleus use; 81% of these adverse effects were related to diarrhea. Other reported adverse effects which occurred at a much lower rate, include nausea, vomiting, and/or constipation. Gastrointestinal effects appear to be dose-related; those taking less than 250 mg of coleus extract did not report any diarrhea, while all patients taking 1000 mg of coleus extract reported diarrhea (100851).

Neurologic/CNS ...Inhalation of forskolin, a constituent of coleus, can cause tremor and restlessness (7281).

Ocular/Otic ...Ophthalmologically, forskolin, a constituent of coleus, can cause stinging of the eyes and conjunctival hyperemia (7283).

Pulmonary/Respiratory ...Inhalation of forskolin, a constituent of coleus, can cause throat and upper respiratory tract irritation, and mild to moderate cough (7281).

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