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Does Leflunomide Interact with Penicillin?

Leflunomide and Penicillin have a unknown drug interaction according to U.S. FDA drug labeling data. In patients taking leflunomide, exposure of drugs which are OAT3 substrates (e.g., cefaclor, cimetidine, ciprofloxacin, penicillin G, ketoprofen, furosemide, methotrexate, zidovudine) may be increased. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.

Severity
Unknown
Leflunomide Class
Antirheumatic Agent
Management
Consult your pharmacist
Data Source
U.S. FDA via OpenFDA

What To Tell Your Doctor or Pharmacist

If you are taking Leflunomide and your doctor is considering prescribing Penicillin (or vice versa), make sure to:

  • Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
  • Ask whether the benefits of combining these medications outweigh the risks for your specific situation
  • Ask what symptoms to watch for that would indicate the interaction is causing problems
  • Never stop or change either medication without first consulting your healthcare provider
💊 Leflunomide(Arava)+💊 Penicillin

Severity & Interaction Details

ℹ️
unknown
Interaction documented — severity unclassified
The FDA label notes an interaction but the severity is not classified in our dataset.
Severity scale
MinorContra
On record
Yes
Drug A class
Antirheumatic Agent
Drug B class
—
Source
FDA drug label - leflunomide

What this means in plain English

In patients taking leflunomide, exposure of drugs which are OAT3 substrates (e.g., cefaclor, cimetidine, ciprofloxacin, penicillin G, ketoprofen, furosemide, methotrexate, zidovudine) may be increased.

About Leflunomide and Penicillin

Leflunomide is an Antirheumatic Agent. Leflunomide is also sold under the brand name Arava. Leflunomide is taken by mouth. Leflunomide additionally carries an FDA boxed warning, the FDA's strongest safety alert.

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Data integrity: Every interaction shown is extracted directly from official U.S. FDA drug labeling via openFDA and the U.S. National Library of Medicine (NIH) — no interactions are invented, inferred, or manually edited. Maintained by CheckDrugInteractions.com. See our methodology or report a correction at support@checkdruginteractions.com.

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.