The combined toxicity of azidothymidine and antimycobacterial agents. A retrospective study

Eight patients being treated for tuberculosis prior to starting azidothymidine therapy (study group) were compared with 56 patients who were treated with azidothymidine but not with antimycobacterial agents (control group). Toxicity was assessed 12 wk after the initiation of treatment with azidothymidine. Study group patients were more likely than control subjects to be either black or Hispanic (75% versus 30%, p = 0.02). There were no other statistically significant demographic differences. Seven study patients, and 20 control subjects experienced a fall in leukocyte count greater than 10% (88% versus 36%, p = 0.01). Within each group, patients with acquired immune deficiency syndrome (AIDS) were more likely to experience this degree of hematologic toxicity than were patients with AIDS-related complex (p = 0.03). However, analysis of covariance showed no significant differences between the groups after 12 wk of azidothymidine with regard to mean leukocyte or platelet counts, hemoglobin levels, or values for tests of liver function. The groups were similar in transfusion requirements and frequency of changes in azidothymidine dosage. Although this study was limited in power by the number of patients and the nonrandomized, retrospective design, the data suggest that patients can tolerate concurrent therapy with azidothymidine and antimycobacterial agents without unacceptable toxicity.