Acetazolamide-associated aplastic anaemia.

Eleven cases of acetazolamide-associated aplastic anaemia were reported in Sweden during a 17-year period. There were six women and five men with a median age of 71 years (range 63-85 years). The median dose of acetazolamide was 500 mg, and the median duration of treatment was 3 months (range 2-71 months). Ten of the eleven patients died, all within 8 weeks after detection of their aplastic anaemia. The relative risk of developing aplastic anaemia when taking acetazolamide was 13.3 (95% confidence limits (CL); 6.8-25.3). The estimated incidence of reported acetazolamide-associated aplastic anaemia is approximately one in 18,000 patient years. The results strongly indicate that acetazolamide treatment is associated with a substantial increase in the risk of developing aplastic anaemia.