Safety and Anti-HIV Activity of Capravirine Alone and in Combination With Other Anti-HIV Drugs

This 2-part study will test the safety and anti-HIV activity of capravirine alone, and the safety, anti-HIV activity, and drug interactions of capravirine combined with other anti-HIV drugs. Capravirine belongs to a class of drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs), which are effective when used together with other drugs, including nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors. Normal volunteers 18 years of age and older may enroll in Part 1 of the study. HIV-infected patients 18 years of age and older who have not previously been treated with a NNRTI (efavirenz, nevirapine, and delavirdine) may participate in Part 2. All prospective study participants will be screened for eligibility with a physical examination, blood tests, a urine test and an electrocardiogram (ECG). Part 1 - Volunteers will be randomly assigned to one of two treatment groups as follows: Group 1 will receive capravirine alone for 7 days and capravirine plus efavirenz (another NNRTI) for an additional 10 days. On day 1, participants will have a physical examination, urine test and laboratory blood tests. Blood samples will be collected just before the first dose of capravirine is given and again at 0.5, 1, 2, 4, 6, 8 and 12 hours after the dose. A small plastic tube will be placed in a vein to avoid multiple needle sticks. On day 8, participants will have another physical examination and laboratory blood tests. Blood samples will be drawn again as described above. In the evening of day 8, efavirenz will be added to the regimen. On day 18 (the last day of the study), participants will have another physical examination and blood tests. Blood will again be collected as described above. Group 2 will take capravirine alone for 8) days and capravirine plus ritonavir (a protease inhibitor) for an additional 8 days. Physical examinations, urine tests, and blood collections will be done as described above on day 1, day 8 and day 16 (the last da