G-Methotrexate Methotrexate Phenytoin
MajorTaking phenytoin with methotrexate (Trexall) may make methotrexate's toxic effects stronger. The leaflet puts phenytoin in the same group as salicylates, phenylbutazone and sulfonamides, and says the toxicity may be increased with all of them. The leaflet also says NSAIDs (painkillers such as ibuprofen or diclofenac) should not be given before, or together with, high doses of Trexall, such as those used to treat osteosarcoma. If you take both phenytoin and methotrexate, your doctor should know, so they can watch you for side effects.
These medicines can affect each other in a serious way. Do not start taking them together unless your doctor has said it is OK. If you already take both, do not stop either one on your own: speak to your doctor or pharmacist soon.