There is a clear risk for development of AIDS in hemophilic patients. AZT administration has been shown to inhibit HIV replication in vitro. Patients taking AZT have experienced fewer opportunistic infections and improvements in measures of immunity. The most common laboratory abnormalities observed with AZT are hematologic. However, the clinical and laboratory toxicity of AZT remains poorly understood in hemophiliacs. Hepatitis and liver dysfunction are more common in this population compared to other groups at risk for HIV infection. Because AZT is largely metabolized in the liver, drug pharmacokinetics needs to be evaluated in this patient population.

Both hemophiliacs and non-hemophiliacs take AZT for a period of 12 weeks. The first dose is administered intravenously. AZT is then given orally every 4 hours while awake (5 doses per day). Patients are evaluated by physical examinations and laboratory assessments. These include HIV culture of blood and leukocyte counts, lymphocyte counts, and lymphocyte subsets measured at study entry and every 4 weeks thereafter. Patients are hospitalized for pharmacokinetic studies at study entry and at Weeks 6 and 12. Each of these studies involves both intravenous and oral administration within 48 hours of one another. Blood is sampled at 0, 0.5, 1, 2, 3, 4, 6, 8, 10, and 12 hours after each administration and urine is collected every 2 hours for 12 hours.