Study Objective: To determine whether zidovudine is effective in increasing the platelet count in patients with thrombocytopenic purpura related to human immunodeficiency virus (HIV) infection.
Design: Nonrandomized controlled trial with two consecutive regimens.
Setting: Immunopathology and hematology clinics at two general hospitals.
Patients: Consecutive sample of 34 patients infected with HIV who had thrombocytopenic purpura (platelets < 50 X 109/L) without visceral bleeding. Twenty-nine patients completed the study; one patient was removed because of drug toxicity.
Interventions: Zidovudine for 12 weeks, 250 mg every 6 hours orally in 10 patients; and 500 mg every 8 hours orally in 24 patients.
Measurements and Main Results: Three of ten patients receiving 250 mg every 6 hours and 12 of 24 patients receiving 500 mg every 8 hours had a persistent increase in their platelet counts. In both groups the mean value of the platelet count increased significantly by week 12; from 28 X 109/L ± 12 (SD) to 57 X 109/L ± 36 in the first group and from 20 X 109/L ± 13 to 77 X 109/L ± 42 in the second group (P < 0.05 and P < 0.01, respectively).
Conclusions: Zidovudine is effective on platelet counts in some patients with HIV-related thrombocytopenia. These results suggest that HIV itself may play a direct or indirect role in the pathogenesis of this disorder.