Drug & supplement interaction

Sweet Clover + Lepirudin

Lepirudin brand name: Refludan.

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

Sweet Clover has a moderate interaction with Lepirudin. Theoretically, fresh sweet clover might increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.

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

Sweet Clover and Lepirudin

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Lepirudin

Lepirudin falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Sweet Clover interacts with.

Theoretically, fresh sweet clover might increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.
Fresh sweet clover contains coumarinic acids, which are converted to free coumarins during drying. Dicoumarol, which has anticoagulant activity, also has been found in some sweet clover preparations and can be formed if fresh sweet clover is allowed to spoil.
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

Lepirudin (Refludan) is a powerful blood thinner given in the hospital, usually by IV, to stop clots from forming. It works directly on thrombin, a key clotting protein. Sweet clover is a different story, but it matters here because spoiled or fermented sweet clover can contain dicoumarol, a compound with its own blood-thinning action. Stack that on top of Lepirudin and you could, in theory, tip the balance toward too much thinning.

The realistic worry is bleeding: easy bruising, nosebleeds, bleeding gums, or more serious internal bleeding. To be fair, this concern is theoretical and based on how these substances behave, not on solid human studies. Still, since Lepirudin is already a strong anticoagulant given in a closely monitored setting, please tell your doctor or pharmacist before using any sweet clover product.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Monographs on the medicinal uses of plant drugs. Exeter, UK: European Scientific Co-op Phytother, 1997.
  2. Wichtl MW. Herbal Drugs and Phytopharmaceuticals. Ed. N.M. Bisset. Stuttgart: Medpharm GmbH Scientific Publishers, 1994.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 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

Sweet Clover Also Interacts With Other Medications

Sweet Clover has 479 moderate known drug interactions in our database — the Lepirudin 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. Lepirudin)
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 Lepirudin

This page covers Sweet Clover only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Lepirudin page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Piracetam (major), Aconite (moderate) and Allspice (moderate).

By severity: 3 major · 190 moderate · 25 minor.

From our pharmacist’s overview on the Lepirudin page

“Lepirudin (Refludan) is a potent injectable blood thinner, typically given when heparin has caused a dangerous platelet reaction, and that makes this a list to read with real care. Of the 218 supplements and herbs with interactions on file, 202 can slow clotting on their own, piling extra bleeding risk onto a drug whose chief hazard is…”

Reviewed by 2 · Jul 18, 2026

Open the Lepirudin 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 Lepirudin 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 Lepirudin 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

#1,382 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Lepirudin
Steady interest

#2,160 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
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 Lepirudin, 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 Lepirudin supplement interactions › Every supplement checked against Lepirudin, 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 Sweet Clover and Lepirudin Together: Common Questions

Can you take Sweet Clover with Lepirudin?
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 Lepirudin 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 Lepirudin 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.