A Study of Dideoxycytidine in HIV-Infected Patients

To determine how much of a dose is absorbed by the body when zalcitabine ( dideoxycytidine; ddC ) is given orally and how long the drug stays in the body after absorption or intravenous (IV) administration. Laboratory tests have shown that ddC is effective in stopping the growth of the HIV in test tubes. The study will reveal the pharmacokinetic (blood levels) properties of this new drug and how long the drug remains in the body at each of six doses. This should be useful background information and should allow a simple and efficient comparative study of any new oral formulation, such as a tablet or capsule, since dose-related problems will already be known. Laboratory tests have shown that ddC is effective in stopping the growth of the HIV in test tubes. The study will reveal the pharmacokinetic (blood levels) properties of this new drug and how long the drug remains in the body at each of six doses. This should be useful background information and should allow a simple and efficient comparative study of any new oral formulation, such as a tablet or capsule, since dose-related problems will already be known. Patients are hospitalized and receive ddC twice, once by mouth and once by IV injection. Each patient receives the drug at one of six increasing doses, and no patient is studied at more than one dose level. Following each dose, toxicity is measured before the next higher dose is given. Several blood samples and urine specimens are taken to permit measurement of the amount of drug in the bloodstream and of the speed with which it is eliminated from the body.