Methotrexate and Ondansetron interaction
Methotrexate and Ondansetron: the Ondansetron prescribing label describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Moderate
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Ondansetron label · effective 2026-04-16
Moderate
In a crossover trial in 76 pediatric patients, intravenous ondansetron did not increase blood levels of high-dose methotrexate.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.