The Effect of Efavirenz and Nelfinavir on the Blood Levels of Certain Lipid-Lowering Drugs

Inclusion Criteria Volunteers may be eligible for this study if they: Are HIV-negative. Are 18 to 60 years old. Weigh at least 50 kg (110 lbs) and are within 30 percent of their ideal body weight. Cannot have children (have reached menopause [change of life] for at least 24 straight months or have had a hysterectomy), if female and enrolling to Group A, B, or C. Have a negative pregnancy test within 14 days before study entry and within 24 hours before starting the study drugs, if female, able to have children, and enrolling to Group D. Agree to avoid trying to become pregnant or causing someone to become pregnant. Agree not to donate sperm or participate in other fertilization procedures. If participating in sexual activity that could lead to pregnancy, the study volunteer and/or partner must use 2 reliable methods of birth control at the same time, while taking study drugs, and for 6 weeks after stopping the drugs. Male volunteers are allowed to be sexually active without the use of birth control if they have had a successful vasectomy or are sterile. Exclusion Criteria Volunteers will not be eligible for this study if they: Have or have had heart, kidney, blood, nerve, digestive, mental, hormonal, or immune system diseases. These include high blood pressure, blocked arteries, arthritis, diabetes, stomach or intestinal problems, depression, and past use of antidepressant drugs. Are pregnant or breast-feeding. Have used experimental, prescription, or over-the-counter drugs within 14 days before study entry, except for aspirin (ASA), acetaminophen (Tylenol), diphenhydramine (Benadryl), daily multivitamins, mineral supplements, birth control pills or implants, and hormone replacement therapy for women who have reached menopause. Are allergic to study drugs or their ingredients. Abuse drugs or alcohol. Have a medical condition that, in the opinion of the investigator, would interfere with their participation in the study. Have participated in any experimental drug study within 30 days before study entry. Are not able to keep their usual diet during the study or are unable to write down their food intake before the study visits. Have an abnormal urine test result, e.g., urinary tract infection, kidney disease, or kidney stones.