The Effects of Zidovudine on the Blood of HIV-Infected Patients

Despite an understanding of the serum (or plasma) pharmacokinetics (blood levels) of AZT, a therapeutic concentration range and optimal dosing interval have not yet been determined.

Three studies are planned on two separate patient groups. Group (1) Patients who have never taken AZT start on a standard dose of AZT. Blood samples are taken hourly for an 8-hour period on days 1 and 14. Other blood samples are taken on days 2, 4, and 8. Group (2) Patients who have never taken AZT are given a standard dose for the first week, increasing each week until week 5. Blood samples are taken at the end of each weekly treatment. After 4 weeks of standard treatment, patients in groups 1 and 2 return and receive a single morning dose of oral AZT. Blood samples are taken immediately before dosing and at 1, 2, 4, 6, and 8 hours after dosing. After a 48-hour clearance period, patients return and resume dosing. Blood samples are again taken over an 8-hour period. After 24 weeks of standard treatment, the pharmacokinetic studies are repeated.