Does Methotrexate Interact with Neomycin?
Methotrexate and Neomycin have a major drug interaction according to U.S. FDA drug labeling data. 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) Proton pump inhibitors Weak acids (e.g., salicylates) Nephrotoxic products Probenecid Nitrous Oxide Coadministration of methotrexate with nitrous oxide anesthesia potentiates the effect of methotrexate on folate-dependent metabolic pathways, which may increase the risk of severe methotrexate adverse reactions. 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
- Major
- Methotrexate Class
- Folate Analog Metabolic Inhibitor
- Management
- Close medical supervision required
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Methotrexate and your doctor is considering prescribing Neomycin (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
- Ask how frequently you should be monitored while these are co-prescribed
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider