Patients must not take sulfa antibiotics, such as co-trimoxazole septra or trimethoprim, while taking methotrexate.

If you experience any of the following symptoms, stop taking methotrexate and call your doctor right away mouth sores, diarrhea, black, tarry, or bloody stools, or vomit that is bloody or looks like coffee grounds.

You are taking other prescription or nonprescription medications including other nsaids, blood pressure medications, diuretics, lithium, antacids, cholestyramine, warfarin, or methotrexate.