AZATHIOPRINE AND LEFLUNOMIDE
The manufacturers say that the concurrent use of leflunomide and azathioprine has not yet been studied but it would be expected to increase the risk of serious adverse reactions (haematological toxicity or hepatotoxicity). Azathioprine is rapidly and extensively metabolised to mercaptopurine. Mercaptopurine is therefore expected to interact similarly.
The manufacturers advise avoiding concurrent use. As the active metabolite of leflunomide has a long half-life of 1 to 4 weeks, a washout with colestyramine or activated charcoal should be given if patients are to be switched to other DMARDs.
The manufacturers advise avoiding concurrent use. As the active metabolite of leflunomide has a long half-life of 1 to 4 weeks, a washout with colestyramine or activated charcoal should be given if patients are to be switched to other DMARDs.