Celecoxib × Methotrexate

NSAIDs can slow renal excretion of methotrexate and increase its blood, gastrointestinal and kidney toxicity (methotrexate SmPCs). For celecoxib itself, no significant effect on methotrexate pharmacokinetics was found at rheumatological doses (celecoxib SmPC). The US celecoxib label (FDA) also states that celecoxib does not change methotrexate pharmacokinetics, but warns that combining NSAIDs with methotrexate may raise the risk of methotrexate toxicity: neutropenia, thrombocytopenia, renal dysfunction.

Mouth ulcers (mucositis), nausea, diarrhoea, hair loss. Blood counts fall: leukocytes, platelets, erythrocytes. Severe cases: fatal pancytopenia, nephrotoxicity.

With high oncological methotrexate doses, NSAIDs are not given before or together with methotrexate (methotrexate 100 mg/ml SmPC). With low rheumatological doses, NSAIDs may continue only under strict medical supervision, and with any kidney impairment, even mild, the combination is not recommended (methotrexate 2.5 mg SmPC). Take care if the NSAID and methotrexate are given within 24 hours of each other, since methotrexate levels can rise (methotrexate 2.5 mg SmPC). While an NSAID is taken, check full blood count and kidney function more often than the usual methotrexate schedule (methotrexate 2.5 mg SmPC). Both celecoxib labels, Spanish and US (FDA), ask for monitoring of methotrexate toxicity, and the US methotrexate label advises close monitoring for methotrexate adverse reactions if the combination cannot be avoided.