Toxizität von azathioprin

This review summarises literature data about the prevalence of azathioprine-induced short-and long-term toxicity available from different diseases. Within a few days, about 4-6% of the patients suffer from vomiting requiring discontinuation of therapy. Azathioprine-induced fever occurs in about 1-2% of the patients. The prevalence of bone marrow toxicity is between 2-12% and is dose-dependent. Liver toxicity is both dose-dependent and dose-independent and occurs in about 3% of the patients. Unfortunately, the detection of the thiopurine methyltransferase (TPMT) cannot predict side effects. Tolerance to azathioprine depends on the existing disease and is higher in patients with vasculitis and connective tissue diseases compared to those with rheumatoid arthritis. There are no convincing data showing an increased risk of malignant diseases induced by azathioprine. The outcome of pregnancies is more dependent on the underlying disease of the patients, malformations of the infants are not significantly increased compared to the normal population and occur in about 3-5% of the pregnancies. In conclusion, at present, azathioprine belongs to the safest drugs in rheumatology.