Drug & supplement interaction

Lithium + Trandolapril, Verapamil

Trandolapril, Verapamil brand name: Tarka.

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

Trandolapril, Verapamil falls into 2 drug categories that Lithium can interact with; the most serious is rated moderate. Theoretically, taking lithium supplements with ACEIs might increase levels and adverse effects of lithium.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Lithium and Trandolapril, Verapamil

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Lithium interacts with whole categories of medication. Trandolapril, Verapamil falls into 2 of those categories, so it can interact with Lithium in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ACE INHIBITORS (ACEIs)

1 of 2

Why this applies to Trandolapril, Verapamil

Trandolapril, Verapamil falls under ACE INHIBITORS (ACEIs) — the group Lithium interacts with.

Theoretically, taking lithium supplements with ACEIs might increase levels and adverse effects of lithium.
Concomitant administration of ACEIs with lithium may increase lithium concentrations. It is unclear if this interaction would be clinically significant with the smaller doses found in lithium supplements.
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 is a combo pill of trandolapril (an ACE inhibitor) plus verapamil. The piece that matters here is the ACE inhibitor side. ACE inhibitors can make your kidneys hold onto a bit more lithium, so lithium levels in your body can slowly creep up. Since lithium has a narrow safety window, even a small rise can lead to warning signs like a fine hand tremor, nausea, increased thirst, confusion, or unsteadiness.

Now, the honest part: this concern is theoretical, based on how these drugs behave rather than strong studies. With the tiny amounts in over-the-counter lithium supplements (like lithium orotate), a meaningful problem is far less likely. Still, please loop in your pharmacist or doctor before combining them, especially if you take prescription lithium.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
  2. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
Moderate

CALCIUM CHANNEL BLOCKERS

2 of 2

Trandolapril, Verapamil also falls under CALCIUM CHANNEL BLOCKERS.

Theoretically, taking lithium supplements with calcium channel blockers might reduce lithium levels and might also increase the risk of certain adverse effects.
Calcium channel blockers might reduce lithium concentrations. Monitor lithium levels with concurrent use. Calcium channel blockers might also increase the adverse neurological and gastrointestinal adverse effects of lithium. It is unclear if these interactions would occur with the smaller doses found in lithium supplements.
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: trandolapril (an ACE inhibitor) plus verapamil (a calcium channel blocker). It's the verapamil part that matters here. In theory, this combo could pull your lithium levels down a bit, which might make lithium work less well, and at the same time it could make lithium's own side effects feel stronger, things like hand tremor, nausea, loose stools, or feeling foggy and unsteady.

I want to be honest with you: this is a theoretical concern based on how these drugs behave, not strong proof, and it's unclear whether the small amounts in lithium supplements like lithium orotate would do anything at all. Still, lithium has a narrow safe range, so please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
  2. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.

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

Lithium Also Interacts With Other Medications

Lithium has 259 major, 255 moderate known drug interactions in our database — the Trandolapril, Verapamil one above is among them. If you take anything else, check it against the full list below.

Major 259 Moderate 255 No known interaction 2,316 (incl. Trandolapril, Verapamil)
Taking anything else?

Check Another of Your Medications Against Lithium

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

From our Q&A

Questions About Lithium or Trandolapril, Verapamil

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Lithium or Trandolapril, Verapamil, 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 Trandolapril, Verapamil

This page covers Lithium 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

One more smart check

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

We hold 330 real supplement products containing Lithium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lithium. Your product may carry other ingredients that interact with Trandolapril, Verapamil too, on top of Lithium — 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 Lithium 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 Lithium
Top 25%

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

29 days ago today
Medication Trandolapril, Verapamil
Top 25%

#524 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 Lithium

What is Lithium?

Lithium
  • Mood support
  • Bipolar disorder (prescription)
  • Healthy mental function
  • Irritability or stress
  • Sleep support

Lithium is a naturally occurring metal that, in prescription form (lithium carbonate or citrate), is an FDA-approved, well-proven treatment for bipolar disorder. Low-dose supplement forms like lithium orotate are sold for mood support, but there is very little reliable evidence that they work, and even small amounts of lithium can be risky for some people. Always talk to a pharmacist or doctor before taking any lithium product.

Read the full Lithium monograph & all interactions
Keep checking

Other Drugs & Lithium

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

259Major
255Moderate
0Minor
2,315No known interaction
259 Major 255 Moderate 2,315 No interaction
Major

259 interactions

Showing 60 of 259 major interactions — see all 259 on the Lithium page.

Moderate

255 interactions

Showing 60 of 255 moderate interactions — see all 255 on the Lithium page.

No interaction 2,315 drugs checked — show the list

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

Showing the 60 most looked-up of 2,315 medications checked with no known interaction — see the full Lithium list.

See the full Lithium 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
Lithium 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 Lithium and Trandolapril, Verapamil Together: Common Questions

Can you take Lithium 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.
Why are there 2 interactions listed for Lithium and Trandolapril, Verapamil?
Trandolapril, Verapamil belongs to more than one drug category, and Lithium 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 Lithium 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

Still Have a Question About Trandolapril, Verapamil and Lithium?

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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.