Does Clarithromycin Interact With Phenytoin?

Other Drugs Metabolized by CYP450 Isoforms Other than CYP3A: Hexobarbital Phenytoin Valproate Use With Caution There have been postmarketing reports of interactions of clarithromycin with drugs not thought to be metabolized by CYP3A, including hexobarbital, phenytoin, and valproate.

Severity: Moderate

Severity basis: drug interactions section (keywords: caution). Combining Clarithromycin (Macrolide antibiotic) and Phenytoin (Anticonvulsant) is classified as a moderate interaction.

What to Do

Use this combination with caution. Your prescriber may monitor you more closely or adjust doses.

From the FDA Label

Other Drugs Metabolized by CYP450 Isoforms Other than CYP3A: Hexobarbital Phenytoin Valproate Use With Caution There have been postmarketing reports of interactions of clarithromycin with drugs not thought to be metabolized by CYP3A, including hexobarbital, phenytoin, and valproate.

Source: FDA structured product labeling (set_id 0be243c6-de02-45dd-8210-cab1bbc8dfa7).

Clarithromycin

Macrolide antibiotic

Brands: Biaxin

View Clarithromycin safety profile

Phenytoin

Anticonvulsant

Brands: Dilantin

View Phenytoin safety profile

Check these against your full medication list in our free Interaction Checker

This information is educational — not medical advice.

This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.

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