Leflunomide

Renal impairment; impaired bone-marrow function including anaemia, leucopenia, or thrombocytopenia (avoid if significant and due to causes other than rheumatoid arthritis); recent treatment with other hepatotoxic or myelotoxic disease-modifying antirheumatic drugs (avoid concomitant use); history of tuberculosis; exclude pregnancy before treatment; effective contraception essential during treatment and for at least 2 years after treatment in women and atleast 3 months after treatment in men (plasma concentration monitoring required; waiting time before conception may be reduced with washout procedures; monitor full blood count (including differential white cell count and platelet count before treatment and every 2 weeks for 6 months then every 8 weeks; maonitor liver function; monitor blood pressure; washout procedures recommended for serious adverse effects and before transferring to other disease-modifying antirheumatic drugs. HEPATOTOXICITY. Potentially life threatening hepatotoxicity reported usually in the first 6 months; monitor liver function before treatment and at least monthly for first 6 months then every 2 months. Discontinue treatment or reduce dose a/c to liver function abnormality; if liver function abnormality persits after dose reduction, discontinue treatment and institute washout procedure. WASHOUT PROCEDURES: To aid drug elemination in case of serious adverse effect, before starting another disease-modifying antirheumatic drug, or before conception, stop treatment give either colestyramine 8g 3 times daily for 11 days or activated charcoal 50g 4 times daily for 11 days; the concentration of active metabolite after washout should be < 20 micrograms /lit (measured on 2 occasions 14 days apart) in men or women before conception.