A few years ago, the immunomodulatory molecule leflunomide was licensed as a new disease modifying anti-rheumatic drug (DMARD) for the treatment of rheumatoid arthritis (RA). Several randomised clinical trials have established its safety and efficacy, which is comparable to that of sulfasalazine and methotrexate.^1,2 Some questions remain about the performance of this agent in current therapeutic strategies.³ One particular important query about the applicability of leflunomide is its use in combination therapy with methotrexate. Although there have been some conflicting opinions, it was shown by van Riel and Weinblatt et al that such combination therapy is safe and more effective than treatment with leflunomide or methotrexate alone.^{4,5 …}