Drug & supplement interaction

Fo-ti + Trandolapril, Verapamil

Trandolapril, Verapamil brand name: Tarka.

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

Trandolapril, Verapamil falls into 4 drug categories that Fo-ti can interact with; the most serious is rated moderate. Theoretically, fo-ti might increase or decrease the levels and clinical effects of drugs metabolized by CYP1A2.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Fo-ti and Trandolapril, Verapamil

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Fo-ti interacts with whole categories of medication. Trandolapril, Verapamil falls into 4 of those categories, so it can interact with Fo-ti in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 4

Why this applies to Trandolapril, Verapamil

Trandolapril, Verapamil falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Fo-ti interacts with.

Theoretically, fo-ti might increase or decrease the levels and clinical effects of drugs metabolized by CYP1A2.
In vitro research suggests that fo-ti might inhibit CYP1A2. Additionally, in vitro research suggests that the degree of CYP1A2 inhibition depends on the type of fo-ti extract (i.e., the raw plant leads to greater inhibition than extensively processed extracts). However, in an animal study, an aqueous extract of fo-ti inhibited CYP1A2 while an alcoholic extract of fo-ti induced CYP1A2. Induction or inhibition of CYP1A2 by fo-ti has not been reported in humans.
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 honest picture with Tarka (the trandolapril and verapamil combo) and Fo-ti. The concern on file is about an enzyme called CYP1A2, and in lab dishes Fo-ti can block it. Trouble is, Tarka isn't really cleared by CYP1A2 in a meaningful way. Verapamil is handled mostly by a different enzyme (CYP3A4), and trandolapril is processed in the liver too, so this particular CYP1A2 note doesn't line up well with how your medicine actually works.

So I wouldn't lose sleep over this specific interaction. It's based only on test-tube and animal data, with nothing seen in real people. That said, both Fo-ti and verapamil can affect the liver, so if you notice unusual tiredness, dizziness, swelling, or a slow heartbeat, check in with your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
  2. Zhang Y, Ding T, Diao T, Deng M, Chen S. Effects of Polygonum multiflorum on the activity of cytochrome P450 isoforms in rats. Pharmazie 2015;70(1):47-54. DOI
  3. Xing Y, Yu Q, Zhou L, et al. Cytochrome P450-mediated herb-drug interaction (HDI) of Polygonum multiflorum Thunb. based on pharmacokinetic studies and in vitro inhibition assays. Phytomedicine 2023;112:154710. PubMed
Moderate

HEPATOTOXIC DRUGS

2 of 4

Trandolapril, Verapamil also falls under HEPATOTOXIC DRUGS.

Theoretically, fo-ti might increase the risk of liver damage when taken with hepatotoxic drugs.
Fo-ti has been linked to liver damage in many reports.
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 simple version: Tarka combines trandolapril (a blood pressure medicine) with verapamil. The concern with Fo-ti isn't about how it changes the way your body handles these drugs. Instead, it's about the liver itself. Processed Fo-ti has been tied to cases of liver injury in a number of reports, and verapamil on its own can occasionally stress the liver too. Stacking two things that can each bother the liver may add up.

To be honest, this is a theoretical, anecdote-based worry, not a proven, common reaction. Still, watch for yellowing of the skin or eyes, dark urine, belly pain, or unusual tiredness. Please loop in your pharmacist or doctor before combining them, and don't stop your Tarka on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Park GJ, Mann SP, Ngu MC. Acute hepatitis induced by Shou-Wu-Pian, a herbal product derived from Polygonum multiflorum. J Gastroenterol Hepatol 2001;16:115-7.
  2. But PP, Tomlinson B, Lee KL. Hepatitis related to the Chinese medicine Shou-wu-pian manufactured from Polygonum multiflorum. Vet Hum Toxicol 1996;38:280-2.
  3. UK Medicines and Healthcare Products Regulatory Agency. Polygonum multiflorum and liver reactions. April 2006. Available at: www.mhra.gov.uk/home/idcplg?IdcService= SS_GET_PAGE&useSecondary=true&ssDocName= CON2023590&ssTargetNodeId= 833 (Accessed 10 May 2
  4. Panis B, Wong DR, Hooymans PM, De Smet PA, Rosias PP. Recurrent toxic hepatitis in a Caucasian girl related to the use of Shou-Wu-Pian, a Chinese herbal preparation. J Pediatr Gastroenterol Nutr 2005;41:256-8. PubMed
  5. Mazzanti G, Battinelli L, Daniele C, et al. New case of acute hepatitis following the consumption of Shou Wu Pian, a Chinese herbal product derived from Polygonum multiflorum. Ann Intern Med 2004;140:E589-90.
  6. Cardenas A, Restrepo JC, Sierra F, Correa G. Acute hepatitis due to shen-min: a herbal product derived from Polygonum multiflorum. J Clin Gastroenterol 2006;40:629-32. PubMed
  7. Laird AR, Ramchandani N, deGoma EM, et al. Acute hepatitis associated with the use of an herbal supplement (Polygonum multiflorum) mimicking iron-overload syndrome. J Clin Gastroenterol 2008;42:861-2. PubMed
  8. Jung KA, Min HJ, Yoo SS, et al. Drug-Induced Liver Injury: Twenty Five Cases of Acute Hepatitis Following Ingestion of Polygonum multiflorum Thunb. Gut Liver 2011;5(4):493-9. PubMed
  9. Yuen, M. F., Tam, S., Fung, J., Wong, D. K., Wong, B. C., and Lai, C. L. Traditional Chinese medicine causing hepatotoxicity in patients with chronic hepatitis B infection: a 1-year prospective study. Aliment.Pharmacol.Ther 10-15-2006;24(8):1179-1186. PubMed
  10. Bae, S. H., Kim, D. H., Bae, Y. S., Lee, K. J., Kim, D. W., Yoon, J. B., Hong, J. H., and Kim, S. H. [Toxic hepatitis associated with Polygoni multiflori]. Korean J.Hepatol. 2010;16(2):182-186. PubMed
  11. Furukawa, M., Kasajima, S., Nakamura, Y., Shouzushima, M., Nagatani, N., Takinishi, A., Taguchi, A., Fujita, M., Niimi, A., Misaka, R., and Nagahara, H. Toxic hepatitis induced by show-wu-pian, a Chinese herbal preparation. Intern.Med. 2010;49(15):1537-1 PubMed
  12. Dong H, Slain D, Cheng J, Ma W, Liang W. Eighteen cases of liver injury following ingestion of Polygonum multiflorum. Complement Ther Med 2014;22(1):70-4. PubMed
  13. Lei X, Chen J, Ren J, et al. Liver damage associated with Polygonum multiflorum Thunb.: a systematic review of case reports and case series. Evid Based Complement Alternat Med 2015;2015:459749.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 4

Trandolapril, Verapamil also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, fo-ti might increase the levels and clinical effects of drugs metabolized by CYP3A4.
In vitro research suggests that fo-ti might inhibit CYP3A4. One in vitro study suggests that the degree of CYP3A4 inhibition may depend on the type of fo-ti extract (i.e., the raw plant leads to greater inhibition than extensively processed extracts). However, this evidence conflicts with animal research suggesting that fo-ti does not inhibit CYP3A4. This interaction has not been reported in humans.
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, and the verapamil part is cleared by a liver enzyme called CYP3A4. In test-tube studies, Fo-ti has shown some ability to slow that enzyme down. If that happened in real life, verapamil levels could creep up, which might mean too much of its effect: dizziness, unusually slow heart rate, constipation, swollen ankles, or lightheadedness when you stand.

Here's the reassuring part. This is only a theoretical concern from lab work, and animal studies didn't agree with it. It has never actually been reported in people. Still, since blood pressure and heart rate are easy to track, it's worth telling your pharmacist or doctor before starting Fo-ti so they can keep an eye on things.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
  2. Zhang Y, Ding T, Diao T, Deng M, Chen S. Effects of Polygonum multiflorum on the activity of cytochrome P450 isoforms in rats. Pharmazie 2015;70(1):47-54. DOI
  3. Xing Y, Yu Q, Zhou L, et al. Cytochrome P450-mediated herb-drug interaction (HDI) of Polygonum multiflorum Thunb. based on pharmacokinetic studies and in vitro inhibition assays. Phytomedicine 2023;112:154710. PubMed
Moderate

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES

4 of 4

Trandolapril, Verapamil also falls under CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES.

Theoretically, fo-ti might increase the levels and clinical effects of drugs metabolized by CYP2C8.
In vitro research suggests that fo-ti might inhibit CYP2C8. However, this interaction has not been reported in humans.
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) and verapamil (a calcium channel blocker). Lab studies hint that Fo-ti may slow down a liver enzyme called CYP2C8, which helps clear some drugs. If that happens, levels of the medicine could creep up a bit, possibly leading to stronger blood-pressure-lowering effects. With this combo, that might mean dizziness, lightheadedness, an unusually slow heartbeat, constipation, or swelling in the ankles.

Here's the honest part: this is only a theoretical concern seen in test-tube research, never actually reported in people. So I wouldn't lose sleep over it. Still, since both Fo-ti and these heart medicines deserve respect, let your pharmacist or doctor know before combining them, and keep an eye on how you feel.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Xing Y, Yu Q, Zhou L, et al. Cytochrome P450-mediated herb-drug interaction (HDI) of Polygonum multiflorum Thunb. based on pharmacokinetic studies and in vitro inhibition assays. Phytomedicine 2023;112:154710. 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

Fo-ti Also Interacts With Other Medications

Fo-ti has 1,256 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.

Moderate 1,256 No known interaction 1,574 (incl. Trandolapril, Verapamil)
Taking anything else?

Check Another of Your Medications Against Fo-ti

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

Everything else you take

See Every Supplement That Interacts With Trandolapril, Verapamil

This page covers Fo-ti 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 Fo-ti as Part of a Dietary Supplement Product? Check It for Interactions

We hold 976 real supplement products containing Fo-ti, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Fo-ti. Your product may carry other ingredients that interact with Trandolapril, Verapamil too, on top of Fo-ti — 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 Fo-ti 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 Fo-ti
Top 25%

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

29 days ago today
Medication Trandolapril, Verapamil
Top 25%

#438 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 Fo-ti

What is Fo-ti?

  • Anti-aging and longevity
  • Hair graying and hair loss
  • General tonic for vitality
  • Constipation
  • High cholesterol

Fo-ti (He Shou Wu) is a root used in traditional Chinese medicine, often promoted for healthy aging and hair. High-quality human evidence for these benefits is limited, and processed Fo-ti has been linked to reports of liver injury, so caution and professional guidance are important.

Read the full Fo-ti monograph & all interactions
Keep checking

Other Drugs & Fo-ti

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

0Major
1,256Moderate
0Minor
1,573No known interaction
1,256 Moderate 1,573 No interaction
Moderate

1,256 interactions

Showing 60 of 1,256 moderate interactions — see all 1,256 on the Fo-ti page.

No interaction 1,573 drugs checked — show the list

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

Showing the 60 most looked-up of 1,573 medications checked with no known interaction — see the full Fo-ti list.

See the full Fo-ti 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
Fo-ti 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 Fo-ti and Trandolapril, Verapamil Together: Common Questions

Can you take Fo-ti 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 4 interactions listed for Fo-ti and Trandolapril, Verapamil?
Trandolapril, Verapamil belongs to more than one drug category, and Fo-ti 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 Fo-ti 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 Fo-ti?

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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.