Drug & supplement interaction

Coleus + Glyceryl trinitrate

Glyceryl trinitrate brand name: Nitronal.

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

Coleus has a major interaction with Glyceryl trinitrate. Theoretically, combining coleus with nitrates might increase the coronary vasodilatory effects.

Read the full interaction report
SeverityMajor
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Coleus and Glyceryl trinitrate

Here is the interaction we found between these two, with the evidence behind it.

Major

NITRATES

Why this applies to Glyceryl trinitrate

Glyceryl trinitrate falls under NITRATES — the group Coleus interacts with.

Theoretically, combining coleus with nitrates might increase the coronary vasodilatory effects.
Forskolin, a constituent of coleus, and nitrates both cause coronary vasodilatory effects.
Severity Major Likelihood Probable Evidence B

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..

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

Here's the thing to know about pairing Coleus with nitroglycerin (Nitronal). Nitroglycerin works by relaxing and widening your blood vessels, which eases chest pain by improving blood flow to the heart. Forskolin, the active compound in Coleus, can do something similar through a different pathway. Stack the two together and you may get more blood vessel widening than you bargained for.

In real life, that could mean lower blood pressure, dizziness, lightheadedness, headache, flushing, or feeling faint when you stand up. This concern is mostly theoretical and based on limited research, so don't panic, but it's worth a quick chat with your pharmacist or doctor before combining them, especially if your blood pressure already runs low.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Baumann G, Felix S, Sattelberger U, Klein G. Cardiovascular effects of forskolin (HL-362) in patients with idiopathic congestiv cardiomyopathy. A comparative study with dobutamine and sodium nitroprusside. J Cardiovasc Pharmacol 1990;16:93-100.
  2. Kramer W, Thormann J, Kindler M, Schlepper M. Effects of forskolin on left ventricular function in dilated cardiomyopathy. Arzneimittelforschung 1987;37:364-7.
  3. Schlepper, M., Thormann, J., and Mitrovic, V. Cardiovascular effects of forskolin and phosphodiesterase-III inhibitors. Basic Res Cardiol 1989;84 Suppl 1:197-212. PubMed

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 28 major, 886 moderate known drug interactions in our database — the Glyceryl trinitrate one above is one of them. If you take anything else, check it against the full list below.

Major 28 Moderate 886 No known interaction 1,916 (incl. Glyceryl trinitrate)
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.

Everything else you take

See Every Supplement That Interacts With Glyceryl trinitrate

This page covers Coleus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Glyceryl trinitrate page lists 2 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Hawthorn (major).

By severity: 2 major.

From our pharmacist’s overview on the Glyceryl trinitrate page

“The irony with glyceryl trinitrate (Nitronal) is that both supplements known to interact with it, hawthorn and coleus, are sold for heart health, exactly the concern of someone using this angina medicine. Both interactions are rated major, and both work the same way.”

Reviewed by 2 · Jul 18, 2026

Open the Glyceryl trinitrate 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 Glyceryl trinitrate 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 Glyceryl trinitrate 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%

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

29 days ago today
Medication Glyceryl trinitrate
Steady interest

#1,902 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
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.

28Major
886Moderate
0Minor
1,915No known interaction
28 Major 886 Moderate 1,915 No interaction
Major

28 interactions

Moderate

886 interactions

Showing 60 of 886 moderate interactions — see all 886 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 Glyceryl trinitrate, 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 Glyceryl trinitrate supplement interactions › Every supplement checked against Glyceryl trinitrate, ranked by severity 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 Glyceryl trinitrate Together: Common Questions

Can you take Coleus with Glyceryl trinitrate?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Coleus and Glyceryl trinitrate interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Glyceryl trinitrate and Coleus?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.