Crystapen Phenoxymethyl Penicillin Methotrexate
MajorPenicillins reduce renal clearance of methotrexate, raising levels and risk of severe myelosuppression and mucositis.
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.
Clinical management: Avoid if possible; otherwise monitor blood counts and methotrexate levels.