Azidothymidine associated with bone marrow failure in the acquired immunodeficiency syndrome (AIDS).

Four patients with the acquired immunodeficiency syndrome, and a history of Pneumocystis carinii pneumonia developed severe pancytopenia (hemoglobin, less than 85 g/L; granulocytes, less than or equal to 0.5 X 10(9)/L; platelets, less than or equal to 30 X 10(9)/L) 12 to 17 weeks after the initiation of azidothymidine (AZT) therapy. The bone marrow was markedly hypocellular in three patients and moderately hypocellular in the fourth. Partial bone marrow recovery was documented within 4 to 5 weeks in three patients, but no marrow recovery has yet occurred in one patient during the more than 6 months since AZT treatment was discontinued. Azidothymidine should be used cautiously, with close monitoring of blood values.