Influence of Probenecid and Quinine on the Pharmacokinetics of Azidothymidine

Because AZT leaves the bloodstream quickly, patients must take the drug frequently to keep adequate amounts in their bodies. Probenecid and quinine may slow down the rate at which AZT leaves the body. Therefore, taking these drugs along with AZT may reduce the amount of AZT needed for treatment. In part I, four patients who are now receiving AZT at the usual dose take part in pharmacokinetic studies (how much of the drug enters the blood stream, what happens to the drug in the body, and how it leaves the body) of AZT defined after a dose while at steady state and then again after a new steady state has been reached following the addition of quinine sulfate. Part II studies the pharmacokinetics of AZT in eight patients receiving AZT at 1 of 2 doses and then at the lower dose of AZT plus probenecid with or without quinine.