Drug & supplement interaction

Rice Protein + Trandolapril, Verapamil

Trandolapril, Verapamil brand name: Tarka.

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

Rice Protein has a moderate interaction with Trandolapril, Verapamil. In laboratory research, hydrolyzed rice protein inhibits angiotensin-converting enzyme (ACE).

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

Rice Protein and Trandolapril, Verapamil

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

Moderate

ACE INHIBITORS (ACEIs)

Why this applies to Trandolapril, Verapamil

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

In laboratory research, hydrolyzed rice protein inhibits angiotensin-converting enzyme (ACE). In animal research, the inhibition of ACE is correlated with a reduction in systolic blood pressure. So far, this effect has not been shown in humans. Theoretically, concomitant use of rice protein and ACE inhibitors may increase the risk of blood pressure becoming too low. Use with caution. ACE inhibitors include benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), and trandolapril (Mavik).
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 deal with Tarka, which combines trandolapril (an ACE inhibitor) with verapamil (a calcium channel blocker). Both ingredients work to lower your blood pressure. Some laboratory and animal studies suggest that broken-down (hydrolyzed) rice protein can also block the same ACE enzyme your trandolapril targets, which could, in theory, nudge your blood pressure down a little more.

I want to be honest about the evidence here: this has only been seen in lab dishes and animals, not in people. It's a theoretical concern, not something well documented. If you do use rice protein regularly, just keep an eye out for signs your pressure dipped too low, like dizziness, lightheadedness when standing, or feeling unusually tired. Check in with your pharmacist or doctor before making any changes.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Li GH, Qu MR, Wan JZ, You JM. Antihypertensive effect of rice protein hydrolysate with in vitro angiotensin I-converting enzyme inhibitory activity in spontaneously hypertensive rats. Asia Pac J Clin Nutr. 2007;16 Suppl 1:275-80.

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

Rice Protein Also Interacts With Other Medications

Rice Protein has 22 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 22 No known interaction 2,808 (incl. Trandolapril, Verapamil)
Taking anything else?

Check Another of Your Medications Against Rice Protein

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

Everything else you take

See Every Supplement That Interacts With Trandolapril, Verapamil

This page covers Rice Protein 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 Rice Protein as Part of a Dietary Supplement Product? Check It for Interactions

We hold 610 real supplement products containing Rice Protein, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rice Protein. Your product may carry other ingredients that interact with Trandolapril, Verapamil too, on top of Rice Protein — 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 Rice Protein 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 Rice Protein
Top half

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

29 days ago today
Medication Trandolapril, Verapamil
Top 25%

#440 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 Rice Protein

What is Rice Protein?

  • Building and maintaining muscle
  • Post-workout recovery
  • Plant-based protein source
  • Meal replacement and shakes
  • Weight management support

Rice protein is a plant-based protein powder made from rice that offers an easy way to add protein to your diet, especially if you avoid dairy or animal products. It is generally considered safe and well tolerated, though on its own it is lower in the amino acid lysine and is often blended with pea protein for a more complete amino acid profile. Talk to your pharmacist or doctor before using it if you have kidney problems or other health conditions.

Read the full Rice Protein monograph & all interactions
Keep checking

Other Drugs & Rice Protein

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

0Major
22Moderate
0Minor
2,807No known interaction
22 Moderate 2,807 No interaction
Moderate

22 interactions

No interaction 2,807 drugs checked — show the list

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

Showing the 60 most looked-up of 2,807 medications checked with no known interaction — see the full Rice Protein list.

See the full Rice Protein 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
Rice Protein 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 Rice Protein and Trandolapril, Verapamil Together: Common Questions

Can you take Rice Protein 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 Rice Protein 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 Rice Protein?

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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.