. 2008 May;4(5):337–347.

Table 4.

Azathioprine Drug Interactions

Drug	Drug-Drug Interaction	Renal Impairment	Hepatic Impairment
Azathioprine	Angiotensin-converting enzyme inhibitors: concomitant therapy may induce anemia and severe leukopenia Allopurinol: may increase serum levels of active metabolite (mercaptopurine) Aminosalicylates (olsalazine, mesalamine, sulfasalazine): may inhibit thiopurine methyltransferase, increasing toxicity and causing leukopenia/myelosuppression Mercaptopurine: azathioprine is metabolized to mercaptopurine; concomitant use may result in profound myelosuppression Warfarin: anticoagulant effect may be decreased	CrCl 10–50 mL/minute: administer 75% of normal dose CrCl <10 mL/minute: administer 50% of normal dose Hemodialysis: dialyzable (−45% removed in 8 hours) Administer dose posthemodialysis: CAPD effects are unknown; CAVH effects are unknown	Use with caution in patients with hepatic impairment