Does Methotrexate Interact With Phenytoin?

The label advises avoiding this combination or using it only under close medical supervision. Talk to your prescriber or pharmacist before combining them.

Interactions like this one can happen when two medicines have overlapping effects, or when one changes how the other is absorbed, broken down, or cleared from the body. Methotrexate is a antimetabolite dmard and Phenytoin is a anticonvulsant; together they are documented as a major interaction. How much this matters depends on your dose, your other medications, and your overall health.

If you have been prescribed both Methotrexate and Phenytoin, do not start, stop, or change either medication on your own — some medicines are unsafe to stop suddenly. Tell your prescriber and pharmacist that you take both so they can decide whether the combination is right for you, adjust the dose, monitor you more closely, or suggest an alternative.

If coadministration cannot be avoided, monitor closely for methotrexate adverse reactions when coadministered with: Oral antibiotics (including neomycin) Antifolate drugs (e.g., dapsone, pemetrexed, pyrimethamine and sulfonamides) Oral or intravenous penicillin or sulfonamide antibiotics Aspirin and other nonsteroidal anti- inflammatory drugs Hepatotoxic products Highly protein-bound drugs (e.g., oral anticoagulants, phenytoin, salicylates, sulfonamides, sulfonylureas, and tetracyclines) Prot…

Source: FDA structured product labeling (set_id 04a95db9-a124-4b97-bd71-1c37a6b3b0c8).