Azathioprine and Cyclophosphamide interaction
Azathioprine and Cyclophosphamide: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Azathioprine (IMURAN) label · effective 2025-11-08
Patients with rheumatoid arthritis previously treated with alkylating agents (cyclophosphamide, chlorambucil, melphalan, or others) may have a prohibitive risk of malignancy if treated with IMURAN.
From the Cyclophosphamide (Frindovyx) label · effective 2026-08-26
…colony-stimulating factor) Increased nephrotoxicity ● Amphotericin B ● Indomethacin: Acute water intoxication has been reported with concomitant use of indomethacin Increase in other toxicities: ● Azathioprine: Increased risk of hepatotoxicity (liver necrosis) ● Busulfan: Increased incidence of hepatic veno-occlusive disease and mucositis has been reported. ● Protease inhibitors:…
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.