Leflunomide

Leflunomide is an antirheumatic agent. Leflunomide is a derivative of isoxazole used for its immunosuppressive and anti-inflammatory properties. As a prodrug, leflunomide is converted to an active metabolite, a77 1726, which blocks dihydroorotate dehydrogenase, a key enzyme of de novo pyrimidine synthesis, thereby preventing the expansion of activated t lymphocytes. This agent also inhibits various protein tyrosine kinases, such as protein kinase c (pkc), thereby inhibiting cell proliferation.