Drug & supplement interaction

Coleus + Diltiazem, Enalapril

Diltiazem, Enalapril brand name: Teczem.

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

Diltiazem, Enalapril falls into 3 drug categories that Coleus can interact with; the most serious is rated major. Theoretically, combining coleus with calcium channel blockers might increase the coronary vasodilatory effects.

Read the full interaction report
SeverityMajor
LikelihoodProbable
Interactions3
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Coleus and Diltiazem, Enalapril

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Coleus interacts with whole categories of medication. Diltiazem, Enalapril falls into 3 of those categories, so it can interact with Coleus in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Major).

Major

CALCIUM CHANNEL BLOCKERS

1 of 3

Why this applies to Diltiazem, Enalapril

Diltiazem, Enalapril falls under CALCIUM CHANNEL BLOCKERS — the group Coleus interacts with.

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.
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

Teczem is a combo pill: diltiazem is a calcium channel blocker that relaxes blood vessels and slows the heart, while enalapril is an ACE inhibitor that also lowers blood pressure. Coleus contains forskolin, which in lab studies can widen blood vessels too. So the worry here is mostly additive: stacking Coleus on top of a medicine that already relaxes vessels could push your blood pressure lower than intended.

If that happens, you might feel dizzy, lightheaded, tired, or flushed, especially when standing up. Keep in mind this interaction is largely theoretical, based on how forskolin behaves in the lab rather than strong human proof. Neither drug here is a prodrug, so the direction is straightforward. Please check with your pharmacist or doctor before adding Coleus.

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.
Moderate

ANTIHYPERTENSIVE DRUGS

2 of 3

Diltiazem, Enalapril also falls under 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.
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

Teczem combines two blood pressure medicines: diltiazem (a calcium channel blocker) and enalapril (an ACE inhibitor). Both already work to relax your blood vessels and bring your pressure down. The concern here is simple addition. Coleus contains forskolin, which in animal studies also seems to lower blood pressure. Stack that on top of a medicine that's doing the same job, and your pressure could drop more than you'd like.

If that happens, you might feel dizzy, lightheaded, tired, or even faint when you stand up too fast. I'll be honest though: this warning is theoretical, based mostly on lab and animal work, not real patient cases. Still, please check with your pharmacist or doctor before adding Coleus, and don't change your Teczem on your own.

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
  4. Lindner, E., Dohadwalla, A. N., and Bhattacharya, B. K. Positive inotropic and blood pressure lowering activity of a diterpene derivative isolated from Coleus forskohli: Forskolin. Arzneimittelforschung 1978;28(2):284-289.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Diltiazem, Enalapril 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

This combo product pairs diltiazem (a calcium channel blocker for blood pressure and heart rate) with enalapril (an ACE inhibitor). The diltiazem part is the piece to watch here. Your liver clears diltiazem using an enzyme called CYP3A4, and lab studies suggest Coleus (forskolin) may nudge that enzyme to work faster. In theory, that could lower diltiazem levels and make it a little less effective, so your blood pressure or heart rate might not be controlled as well.

I'll be honest: this is based only on test-tube research, not real patients, so it's a soft concern rather than a red flag. Forskolin can also lower blood pressure on its own, which muddies things further. Before adding Coleus, please run it by your pharmacist or doctor.

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

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 Diltiazem, Enalapril one above is among them. If you take anything else, check it against the full list below.

Major 28 Moderate 886 No known interaction 1,916 (incl. Diltiazem, Enalapril)
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 Diltiazem, Enalapril

This page covers Coleus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diltiazem, Enalapril page lists 271 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Grapefruit (major).

By severity: 9 major · 220 moderate · 42 minor.

From our pharmacist’s overview on the Diltiazem, Enalapril page

“Anyone taking Teczem (diltiazem with enalapril) for blood pressure should know that most of the 271 supplements with an interaction on file hit the same targets as the drug itself. The bulk either add to its blood-pressure-lowering effect or change how the body handles diltiazem, which is processed by an enzyme called CYP3A4.”

Reviewed by 2 · Jul 18, 2026

Open the Diltiazem, Enalapril 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 Diltiazem, Enalapril 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 Diltiazem, Enalapril 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%

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

29 days ago today
Medication Diltiazem, Enalapril
Steady interest

#1,841 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 Diltiazem, Enalapril, 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 Diltiazem, Enalapril supplement interactions › Every supplement checked against Diltiazem, Enalapril, 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 Diltiazem, Enalapril Together: Common Questions

Can you take Coleus with Diltiazem, Enalapril?
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.
Why are there 3 interactions listed for Coleus and Diltiazem, Enalapril?
Diltiazem, Enalapril 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 Diltiazem, Enalapril 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 Diltiazem, Enalapril 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.