Drug & supplement interaction

Sweet Clover + Ambrisentan

Ambrisentan brand names: Letairis, Volibris.

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

Sweet Clover has a moderate interaction with Ambrisentan. Theoretically, concomitant use of sweet clover with hepatoxic drugs might increase the risk of hepatotoxicity.

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

Sweet Clover and Ambrisentan

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

Moderate

HEPATOTOXIC DRUGS

Why this applies to Ambrisentan

Ambrisentan falls under HEPATOTOXIC DRUGS — the group Sweet Clover interacts with.

Theoretically, concomitant use of sweet clover with hepatoxic drugs might increase the risk of hepatotoxicity.
Orally, large amounts of sweet clover can cause transient liver injury in susceptible individuals, possibly due to coumarin content. In one case report, a patient with multiple sclerosis developed jaundiced palms and a slight elevation in serum alanine aminotransferase (ALT) after taking sweet clover containing coumarin 10 mg daily for 3 years. Two weeks after starting therapy with subcutaneous interferon (IFN)-beta 1b, aspartate transaminase (AST) and ALT levels increased to 7 and 17 times the upper limit of normal, respectively. Levels normalized after discontinuation of both products. Subsequent use of IFN-beta 1a alone, without sweet clover, resulted in only a very slight increase in AST.
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 thing to keep in mind with ambrisentan (Letairis): it already carries a real risk of stressing the liver, which is why your doctor checks your liver enzymes regularly while you're on it. Sweet clover contains coumarin, and in high or concentrated amounts it has been linked to its own mild liver irritation in some people.

So the worry here isn't that one changes how the other is broken down. It's that two things that can each bother the liver might add up. This is a theoretical concern based on how they work, not proven harm, and small culinary amounts are unlikely to matter much. Still, with a medication this important, I'd skip the supplement unless your pharmacist or doctor okays it and watch for fatigue, nausea, or yellowing of the skin or eyes.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Tamura S, Warabi Y, Matsubara S. Severe liver dysfunction possibly caused by the combination of interferon beta-1b therapy and melilot (sweet clover) supplement. J Clin Pharm Ther 2012;37(6):724-5. 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

Sweet Clover Also Interacts With Other Medications

Sweet Clover has 479 moderate known drug interactions in our database — the Ambrisentan one above is one of them. If you take anything else, check it against the full list below.

Moderate 479 No known interaction 2,351 (incl. Ambrisentan)
Taking anything else?

Check Another of Your Medications Against Sweet Clover

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

Everything else you take

See Every Supplement That Interacts With Ambrisentan

This page covers Sweet Clover only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ambrisentan page lists 256 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), Beer (major) and Grapefruit (major).

By severity: 9 major · 210 moderate · 37 minor.

Open the Ambrisentan interaction page

One more smart check

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

We hold 26 real supplement products containing Sweet Clover, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sweet Clover. Your product may carry other ingredients that interact with Ambrisentan too, on top of Sweet Clover — 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 Sweet Clover and Ambrisentan 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 Sweet Clover
Steady interest

#1,375 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Ambrisentan
Steady interest

#1,570 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 Sweet Clover

What is Sweet Clover?

Sweet Clover
  • Varicose veins and poor circulation
  • Leg swelling (edema)
  • Hemorrhoids
  • Bruising and minor inflammation
  • Respiratory complaints

Sweet clover is a traditional European herb most often promoted for vein problems and leg swelling, but high-quality human evidence is limited. It contains coumarin, which can become dangerous if the plant spoils, so quality matters and you should talk to a pharmacist before using it.

Read the full Sweet Clover monograph & all interactions
Medication

About Ambrisentan

What Is Ambrisentan Used For?

Brand names: Letairis, Volibris

Ambrisentan tablets and Letairis tablets are both used to treat pulmonary arterial hypertension (PAH, WHO Group 1) — a condition where the blood pressure in the arteries leading to the lungs is dangerously high. Both are approved to help adults exercise better and slow the worsening of PAH.

Both ambrisentan tablets and Letairis are also approved to be used together with tadalafil (another PAH medicine) to further reduce the risk of disease progression, lower the chance of hospitalization for worsening PAH, and improve exercise ability. Most of the clinical evidence was in patients with mild-to-moderate symptoms and PAH caused by unknown or inherited causes, or PAH linked to connective tissue diseases.

See full Ambrisentan drug information
Keep checking

Other Drugs & Sweet Clover

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

0Major
479Moderate
0Minor
2,350No known interaction
479 Moderate 2,350 No interaction
Moderate

479 interactions

Showing 60 of 479 moderate interactions — see all 479 on the Sweet Clover page.

No interaction 2,350 drugs checked — show the list

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

Showing the 60 most looked-up of 2,350 medications checked with no known interaction — see the full Sweet Clover list.

See the full Sweet Clover interactions page
See every supplement checked against Ambrisentan, 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
Sweet Clover monograph › Uses, safety, and every drug interaction in one place Ambrisentan supplement interactions › Every supplement checked against Ambrisentan, ranked by severity Ambrisentan drug information › The full plain-English guide to this medication 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 Sweet Clover and Ambrisentan Together: Common Questions

Can you take Sweet Clover with Ambrisentan?
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 Sweet Clover and Ambrisentan 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 Ambrisentan and Sweet Clover?

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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.