Major
Iopromide × Methotrexate
X-ray contrast media. Watersoluble nephrotropic low-osmolar iodinated agents×Antimetabolites, folic acid analogues
Mechanism
Contrast-induced nephropathy lowers renal methotrexate clearance. At high oncologic methotrexate doses, plasma levels rise and severe toxicity risk (pancytopenia, mucositis, nephrotoxicity) increases.
Symptoms
Stomatitis, diarrhoea, falling leukocyte, platelet, and erythrocyte counts. Severe cases include fatal pancytopenia and acute kidney injury. Symptoms appear 3–7 days after contrast.
Management
At oncologic methotrexate doses, postpone contrast studies for 2–4 weeks after methotrexate administration. If contrast is urgent, ensure adequate hydration and check full blood count and creatinine daily. Add folinic acid rescue.