Aplastic anemia due to chemicals and drugs: a study of 108 patients.

To illustrate the etiologic role of drugs and chemicals in the development of aplastic anemia, we analyzed 108 cases of aplastic anemia among 3,715 hematologic patients during a ten-year period at the hematology section of Istanbul Medical School. Among these 3,715 patients, 695 had leukemia, a result indicating the relative rarity of aplastic anemia as compared with leukemia. Of the 108 patients, 58.3% were male and 41.7% were female. Their ages ranged from six months to 82 years. Pancytopenia was severe in 42.6% of the patients, and moderate or mild in 57.4%. Bone marrow was hypocellular in 84 patients, normocellular in 16, and hypercellular in eight. In 52 (48.1%) of the patients with aplastic anemia, the following etiologic factors were implicated: benzene (25 patients), antirheumatic drugs (ten), chloramphenicol (four), chloramphenicol plus hepatitis or chromosome anomalies (two), thiamphenicol plus sulfonamide (one), antituberculous drugs (three), daraprim (three), insecticides (two), hepatitis (one), and sulfonamide (one). Data indicate that the degree of bone-marrow cellularity is not always related to functional capacity, and numerous agents may have etiologic roles in the development of aplastic anemia.