Drug & supplement interaction

Coleus + Warfarin

Warfarin brand name: Warfarin.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Warfarin falls into 4 drug categories that Coleus can interact with; the most serious is rated moderate. Theoretically, taking coleus may affect drugs metabolized by CYP2C9 and increase the risk of adverse effects or reduce the effectiveness.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Coleus and Warfarin

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Coleus interacts with whole categories of medication. Warfarin falls into 4 of those categories, so it can interact with Coleus in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

1 of 4

Why this applies to Warfarin

Warfarin falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Coleus interacts with.

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.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the situation with warfarin and Coleus. Your liver uses an enzyme called CYP2C9 to clear warfarin from your body, and Coleus (through its forskolin) may tinker with that same enzyme. The tricky part is the lab evidence pulls in both directions: some studies suggest Coleus speeds the enzyme up, others suggest it slows it down. So we honestly can't predict which way your warfarin would shift.

Why this matters: warfarin is a narrow window drug. Too much and you risk bruising, nosebleeds, or serious bleeding; too little and a clot could slip through. Even small swings show up on your INR blood test. This is theoretical and based on lab work, not human cases, so don't panic. Just check with your pharmacist or doctor before adding Coleus, and never change your warfarin on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yokotani K, Chiba T, Sato Y, et al. Hepatic cytochrome P450 mediates interaction between warfarin and Coleus forskohlii extract in vivo and in vitro. J Pharm Pharmacol. 2012;64(12):1793-801.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 4

Warfarin also falls under 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.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the situation with Coleus and warfarin. Lab research hints that Coleus may rev up a liver enzyme (CYP3A4) that helps break down warfarin. If that happened in real life, your body could clear warfarin a little faster, which might weaken its blood-thinning power and, in theory, leave you slightly less protected against clots.

I want to be honest, though: this is based only on test-tube and animal data, so we really don't know if it matters in people. The bigger point is that warfarin is a narrow-therapeutic-index drug, meaning even small shifts can throw off your INR. Don't start or stop anything on your own. Just check with your pharmacist or doctor first, and they can watch your INR more closely if needed.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ding, X. and Staudinger, J. L. Induction of drug metabolism by forskolin: the role of the pregnane X receptor and the protein kinase a signal transduction pathway. J Pharmacol Exp Ther 2005;312(2):849-856. PubMed
  2. Staudinger, J. L., Ding, X., and Lichti, K. Pregnane X receptor and natural products: beyond drug-drug interactions. Expert.Opin Drug Metab Toxicol 2006;2(6):847-857. PubMed
Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

3 of 4

Warfarin also falls under 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.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist if you take warfarin and are eyeing a Coleus (forskolin) supplement. Warfarin already thins your blood by lowering your clotting ability. Coleus may add a separate, mild blood-thinning effect of its own, because in lab and animal studies its active compound forskolin appears to make platelets (the tiny cells that help form clots) less sticky. Stack the two and you could, in theory, bleed or bruise more easily, think nosebleeds, bleeding gums, or bruises that show up out of nowhere.

I'll be honest, this is a theoretical concern based on test-tube and animal data, not solid human studies, so don't panic. Still, warfarin is a tricky drug where small shifts matter, so please don't add Coleus without checking with your doctor or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Christenson JT, Thulesius O, Nazzal MM. The effect of forskolin on blood flow, platelet metabolism, aggregation and ATP release. Vasa 1995;24:56-61.
  2. Agarwal KC, Zielinski BA, Maitra RS. Significance of plasma adenosine in the antiplatelet activity of forskolin: potentiation by dipyridamole and dilazep. Thromb Haemost 1989;61:106-10. DOI
  3. Agarwal KC, Parks RE. Forskolin: a potential antimetastatic agent. Int J Cancer 1983;32:801-4. PubMed
Moderate

WARFARIN (Coumadin)

4 of 4
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.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the honest picture with Coleus and warfarin. Warfarin is cleared from your body mainly by a liver enzyme called CYP2C9. The tricky part is that lab studies pull in two different directions: some animal research suggests Coleus speeds that enzyme up (which could weaken warfarin and let a clot slip through), while other test-tube work suggests it slows the enzyme down (which could let warfarin build up and raise your bleeding risk, think easy bruising, nosebleeds, or blood in the urine).

So we genuinely can't say which way it would tip. And because warfarin is a narrow-window drug where even small shifts matter, I'd play it safe. Please loop in your pharmacist or doctor before adding Coleus, and don't change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yokotani K, Chiba T, Sato Y, et al. Hepatic cytochrome P450 mediates interaction between warfarin and Coleus forskohlii extract in vivo and in vitro. J Pharm Pharmacol. 2012;64(12):1793-801.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Coleus Also Interacts With Other Medications

Coleus has 29 major, 885 moderate known drug interactions in our database — the Warfarin one above is among them. If you take anything else, check it against the full list below.

Major 29 Moderate 885 No known interaction 1,916 (incl. Warfarin)
Taking anything else?

Check Another of Your Medications Against Coleus

Covers the 2,830 medications we’ve checked against Coleus. Pick one to open its full report.

From our Q&A

Questions About Coleus or Warfarin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Coleus or Warfarin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Warfarin

This page covers Coleus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Warfarin page lists 361 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alfalfa (major), American Ginseng (major), Beer (major) and Cannabis (major).

By severity: 16 major · 301 moderate · 44 minor.

From our pharmacist’s overview on the Warfarin page

“People take warfarin to prevent dangerous clots, and many are the same people reaching for glucosamine for sore joints or a multivitamin containing vitamin K, which makes this a list that deserves genuine respect. Of the 361 supplements on file for warfarin, 16 carry a major rating, and the danger runs in both directions: some add to w…”

Reviewed by 2 · Jul 18, 2026

Open the Warfarin interaction page

One more smart check

Taking Coleus as Part of a Dietary Supplement Product? Check It for Interactions

We hold 803 real supplement products containing Coleus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Coleus. Your product may carry other ingredients that interact with Warfarin too, on top of Coleus — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Coleus and Warfarin Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Coleus
Top 25%

#238 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Warfarin
Top 10

#4 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Coleus

What is Coleus?

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

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.

Read the full Coleus monograph & all interactions
Medication

About Warfarin

What Is Warfarin Used For?

Brand name: Warfarin

Warfarin sodium tablets and Jantoven tablets are both used to prevent and treat venous thrombosis (blood clots in the veins) and pulmonary embolism (a clot in the lungs). They are also used to prevent clot-related complications in people with atrial fibrillation (an irregular heart rhythm) or who have had a heart valve replaced.

In people who have had a heart attack, warfarin is used to reduce the risk of death, another heart attack, stroke, or other clotting events. It does not dissolve an existing clot, but it helps prevent the clot from growing and stops new dangerous clots from forming.

See full Warfarin drug information
Keep checking

Other Drugs & Coleus

Browse every other medication we’ve checked against Coleus — both the ones with a known interaction and the ones without. Select any drug for the full detail.

29Major
885Moderate
0Minor
1,915No known interaction
29 Major 885 Moderate 1,915 No interaction
Major

29 interactions

Moderate

885 interactions

Showing 60 of 885 moderate interactions — see all 885 on the Coleus page.

No interaction 1,915 drugs checked — show the list

We also checked Coleus against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,915 medications checked with no known interaction — see the full Coleus list.

See the full Coleus interactions page
See every supplement checked against Warfarin, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Coleus monograph › Uses, safety, and every drug interaction in one place Warfarin supplement interactions › Every supplement checked against Warfarin, ranked by severity Warfarin drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Coleus and Warfarin Together: Common Questions

Can you take Coleus with Warfarin?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 4 interactions listed for Coleus and Warfarin?
Warfarin belongs to more than one drug category, and Coleus interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Coleus and Warfarin interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Warfarin and Coleus?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.