Drug & supplement interaction

Bog Labrador Tea + Trandolapril, Verapamil

Trandolapril, Verapamil brand name: Tarka.

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

Bog Labrador Tea has a moderate interaction with Trandolapril, Verapamil. In vitro research shows that aqueous and ethanolic extracts of Bog Labrador tea leaves can increase the concentration of cytochrome P450 3A4 (CYP3A4) enzymes.

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

Bog Labrador Tea and Trandolapril, Verapamil

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Trandolapril, Verapamil

Trandolapril, Verapamil falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Bog Labrador Tea interacts with.

In vitro research shows that aqueous and ethanolic extracts of Bog Labrador tea leaves can increase the concentration of cytochrome P450 3A4 (CYP3A4) enzymes. Extracts obtained from different geographical regions in Quebec resulted in differing potency of CYP3A4 induction. Bog Labrador tea might increase the metabolism of CYP3A4 substrates.
Drugs metabolized by CYP3A4 include lovastatin (Mevacor), clarithromycin (Biaxin), cyclosporine (Neoral, Sandimmune), diltiazem (Cardizem), estrogens, indinavir (Crixivan), amiodarone (Cordarone), ticagrelor (Brilinta), triazolam (Halcion), and others.
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

Tarka combines two blood pressure medicines: verapamil (a calcium channel blocker that your liver clears through the CYP3A4 enzyme) and trandolapril (an ACE inhibitor). The lab research here suggests Bog Labrador tea might speed up that CYP3A4 enzyme. If that happened in your body, you could break down verapamil faster, which may make it less effective. In real life, that could show up as your blood pressure creeping back up, or your heart rate not being controlled as well.

I want to be honest about how thin this evidence is: it comes only from test-tube studies, not from people, and the effect varied a lot between samples. So I wouldn't lose sleep over it, but since blood pressure control matters, please check with your pharmacist or doctor before adding this tea regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Tam TW, Liu R, Saleem A, et al. The effect of Cree traditional medicinal teas on the activity of human cytochrome P450-mediated metabolism. J Ethnopharmacol. 2014;155(1):841-6. 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

Bog Labrador Tea Also Interacts With Other Medications

Bog Labrador Tea has 642 moderate known drug interactions in our database — the Trandolapril, Verapamil one above is one of them. If you take anything else, check it against the full list below.

Moderate 642 No known interaction 2,188 (incl. Trandolapril, Verapamil)
Taking anything else?

Check Another of Your Medications Against Bog Labrador Tea

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

Everything else you take

See Every Supplement That Interacts With Trandolapril, Verapamil

This page covers Bog Labrador Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trandolapril, Verapamil page lists 304 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 Beer (major).

By severity: 11 major · 250 moderate · 43 minor.

From our pharmacist’s overview on the Trandolapril, Verapamil page

“This is one of the supplement lists I would want a patient to read closely, not skim. Tarka combines trandolapril and verapamil to lower blood pressure, and most of these interactions pull on that same lever, either dropping pressure further than intended or working against the medicine altogether.”

Reviewed by 2 · Jul 18, 2026

Open the Trandolapril, Verapamil interaction page

How much people look this up

Where Bog Labrador Tea and Trandolapril, Verapamil 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 Bog Labrador Tea
Steady interest

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

29 days ago today
Medication Trandolapril, Verapamil
Top 25%

#387 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 Bog Labrador Tea

What is Bog Labrador Tea?

Bog Labrador Tea
  • Coughs and respiratory complaints
  • Digestive upset and diarrhea
  • Anxiety and stress
  • As a warm beverage
  • Aches and pains (traditional use)

Bog Labrador tea is a wetland shrub whose leaves have long been brewed as a traditional beverage and folk remedy, especially among Indigenous peoples of North America. There is very little human research to confirm any health benefit, and the plant is closely related to species that contain toxic compounds, so it should be used cautiously and in moderation. Pregnant or breastfeeding people should avoid it, and anyone considering it should talk with a pharmacist or doctor first.

Read the full Bog Labrador Tea monograph & all interactions
Keep checking

Other Drugs & Bog Labrador Tea

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

0Major
642Moderate
0Minor
2,187No known interaction
642 Moderate 2,187 No interaction
Moderate

642 interactions

Showing 60 of 642 moderate interactions — see all 642 on the Bog Labrador Tea page.

No interaction 2,187 drugs checked — show the list

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

Showing the 60 most looked-up of 2,187 medications checked with no known interaction — see the full Bog Labrador Tea list.

See the full Bog Labrador Tea interactions page
See every supplement checked against Trandolapril, Verapamil, 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
Bog Labrador Tea monograph › Uses, safety, and every drug interaction in one place Trandolapril, Verapamil supplement interactions › Every supplement checked against Trandolapril, Verapamil, 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 Bog Labrador Tea and Trandolapril, Verapamil Together: Common Questions

Can you take Bog Labrador Tea with Trandolapril, Verapamil?
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.
How serious is the Bog Labrador Tea and Trandolapril, Verapamil 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

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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.