After the washout period, patients will take capravirine once a day in the morning for 6 days. After each dose, a small amount of blood will be drawn at 8 different times over 12 hours to measure the activity of the drug and HIV blood levels. A heparin lock will be placed in the vein to avoid multiple needlesticks. After the 6 days of capravirine there will be another washout period, this time for 21 days. During this time, doctors will determine the optimum combination therapy for the individual patient.