Table 1:

Notable drug–drug interactions with azathioprine1,4,10

Drug classDrug effect or interaction
Aminosalicylates

  • Sulfasalazine

  • 5-aminosalicylic acid

Inhibits thiopurine methyltransferase pathway of azathioprine metabolism
Angiotensin-converting-enzyme inhibitorsReported to induce anemia and leukopenia when used concurrently with azathioprine among patients who have had a renal transplant
WarfarinAzathioprine may inhibit the anticoagulant effect of warfarin
Xanthine oxidase inhibitors

  • Allopurinol

  • Febuxostat

Inhibits the xanthine oxidase pathway of azathioprine metabolism