Herb & supplement monograph

Coleus Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Coleus interacts with medications. The heart of this page is the interaction list — every drug Coleus is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Coleus is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Coleus Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a serious Coleus drug interaction is moderate for most people, and it deserves real caution if you take certain heart or blood pressure medicines. A small number of interactions are rated major with reasonably good documentation, while the large remainder are moderate and mostly theoretical.

Interactions deserving the most attention

The best-supported concerns involve heart medications. Coleus contains forskolin, which widens blood vessels in the heart, so combining it with calcium channel blockers or nitrates could add to that effect. It may also add to the effect of blood pressure medicines, raising the chance of pressure dropping too low. There is also a theoretical concern with warfarin and other blood thinners, since lab and animal research suggests coleus could affect bleeding risk or how warfarin is cleared.

What the rest of the list means

Coleus is listed with hundreds of medications, but that does not mean every combination is harmful. Most entries are theoretical, based on lab or animal findings that coleus might change enzymes the body uses to clear many drugs. Some of that research even points in opposite directions, so the real-world effect in people is not yet clear.

Check your medications against Coleus

Based on HelloPharmacist’s Coleus interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Coleus

917 medications have a known interaction with Coleus, graded by severity. Select any drug for the full evidence-based detail.

29 major interactions. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with Coleus.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Coleus using our pharmacist-reviewed interaction data.

AI summaries are generated from our Coleus interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Coleus combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Coleus affects

Every type of medication (drug category) Coleus is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 7 drug categories Coleus interacts with

Calcium Channel BlockersNitratesAnticoagulant/antiplatelet DrugsAntihypertensive DrugsCytochrome P450 2c9 (cyp2c9) SubstratesCytochrome P450 3a4 (cyp3a4) SubstratesWarfarin (coumadin)

Calcium Channel Blockers

Theoretically, combining coleus with calcium channel blockers might increase the coronary vasodilatory effects.
Forskolin, a constituent of coleus, and calcium channel blockers both cause coronary vasodilatory effects.

Likelihood Probable Evidence B

Nitrates

Theoretically, combining coleus with nitrates might increase the coronary vasodilatory effects.
Forskolin, a constituent of coleus, and nitrates both cause coronary vasodilatory effects.

Likelihood Probable Evidence B

Anticoagulant/Antiplatelet Drugs

Theoretically, concomitant use of coleus and anticoagulant or antiplatelet drugs might increase the risk of bruising and bleeding.
In vitro and animal research shows that forskolin, a constituent of coleus, can inhibit platelet aggregation and adhesion.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, combining coleus with antihypertensive drugs might cause additive blood pressure lowering effects and increase the risk of hypotension.
Animal research shows that forskolin, a constituent of coleus, may lower blood pressure.

Likelihood Possible Evidence D

Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, taking coleus may affect drugs metabolized by CYP2C9 and increase the risk of adverse effects or reduce the effectiveness.
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. Until more is known, advise patients that taking coleus might increase or decrease levels of drugs metabolized by CYP2C9.

Likelihood Possible Evidence D

Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, taking coleus might decrease serum levels of drugs metabolized by CYP3A4.
In vitro research shows that coleus can activate the nuclear receptor, pregnane X receptor (PXR), which results in increased expression of CYP3A4. Although the clinical significance of this is not known, use caution when considering concomitant use of coleus and other drugs affected by these enzymes.

Likelihood Possible Evidence D

Warfarin (Coumadin)

Theoretically, taking coleus may affect the metabolism of warfarin and increase the risk of adverse effects or reduce the effectiveness.
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. 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.

Likelihood Possible Evidence D

Monograph

Coleus: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Coleus is a plant from the mint family whose root contains a compound called forskolin, often marketed for weight loss, asthma, and heart health. While early lab and small human studies are interesting, solid proof that Coleus supplements help any of these conditions is limited. Talk to your pharmacist or doctor before using it, especially if you have heart problems or low blood pressure.

Scientific name: Coleus forskohlii
Family: Lamiaceae
Part used: Roots (source of forskolin)
Common forms: Capsules, tablets, standardized extracts (often standardized to forskolin), powders

People commonly use it for

Weight management
Asthma and breathing
High blood pressure
Heart conditions
Glaucoma (eye pressure)
Exercise and body composition

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

May lower blood pressure and is not well studied for long-term use, so use with care and professional guidance.

PregnancyPossibly Unsafe

When used orally. Evidence from animal research suggests that high doses of coleus can inhibit embryo implantation and/or delay fetal development; avo...

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Coleus (Coleus forskohlii) is a flowering plant in the mint family (Lamiaceae). It grows naturally in warm, tropical parts of Asia and Africa, such as India and Nepal, and has long been used in traditional Ayurvedic medicine.

The part used for supplements is usually the root, which contains an active compound called forskolin. Many products are standardized to a certain percentage of forskolin. People take Coleus for a wide range of reasons, including weight loss, asthma, high blood pressure, and heart health.

How it works

The main active compound in Coleus is forskolin. In laboratory studies, forskolin activates an enzyme called adenylate cyclase, which raises a cell signaling molecule known as cyclic AMP (cAMP).

Higher cAMP levels can affect many body processes, such as relaxing smooth muscle (which may widen airways and blood vessels), influencing heart muscle, and changing how the body breaks down fat. These effects are mostly seen in lab and animal studies, and it is not clear how well they translate to people taking oral Coleus supplements, since the amount of forskolin that actually reaches the bloodstream may be limited.

Effectiveness

Does Coleus work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 16 uses evaluated

16 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Coleus, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 16 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Angina