Major
Ketorolac × Methotrexate
Non-steroidal anti-inflammatory drugs (NSAIDs)×Antimetabolites, folic acid analogues
Mechanism
Ketorolac reduces renal methotrexate clearance and suppresses tubular secretion. At high oncologic methotrexate doses: risk of severe toxicity (pancytopenia, nephrotoxicity, mucositis).
Symptoms
Mouth ulcers (mucositis), nausea, diarrhoea, hair loss. Blood counts fall: leukocytes, platelets, erythrocytes. Severe cases: fatal pancytopenia, nephrotoxicity.
Management
At oncologic methotrexate doses, the combination is not prescribed. At low rheumatologic doses, avoid ketorolac; use paracetamol or a short opioid course for analgesia. Ketorolac courses never exceed 5 days.