Phase I Pharmacokinetic and Tolerance Study of Ribavirin in Human Immunodeficiency Virus (HIV) - Infected Patients

To determine how fast ribavirin reaches the bloodstream, what concentration of ribavirin is reached in blood and how long it remains in the blood (pharmacokinetics) when given by different routes of administration. To find the maximum tolerated dose (MTD) of ribavirin. The effects of ribavirin on the immune system, and on the virus will be measured by T4 cell count and p24 antigen levels. Early studies with ribavirin in patients with AIDS and AIDS related complex (ARC) have shown that ribavirin appears to inhibit the spread of the virus. Determination of how much and how often to give the drug will require further knowledge of the pharmacokinetics and toxicity of the drug in patients with AIDS or ARC and in chronic virus carriers who do not have symptoms. Early studies with ribavirin in patients with AIDS and AIDS related complex (ARC) have shown that ribavirin appears to inhibit the spread of the virus. Determination of how much and how often to give the drug will require further knowledge of the pharmacokinetics and toxicity of the drug in patients with AIDS or ARC and in chronic virus carriers who do not have symptoms. Ribavirin is given to HIV-infected patients intravenously as a timed 30-min infusion at 1 of 5 single doses; 2 weeks later, the same doses are given orally in a single dose. Following at least 2 additional weeks, 6 patients are then given ribavirin at the lowest dose twice a day for 16 weeks. They are evaluated for tolerance and the next group is given a higher dose. Each successive group begins at 3-week intervals to receive doses that increase each day until the MTD is reached. Blood samples taken periodically during the treatment period and for 8 weeks after treatment is stopped are used to measure blood levels of ribavirin and to determine the effects of ribavirin on the HIV and immune system of the patients.