Inclusion Criteria

Patients must have:

• Positive serum antibody to HIV-1 by ELISA or Western blot.
• CD4 count >= 500 cells/mm3 within 2 months prior to study entry, with two additional counts averaging >= 450 cells/mm3 at baseline and on study day 0 (taken at least 48 hours apart).
• No AIDS-defining disease.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms and conditions are excluded:

• More than four loose stools per day.
• Participation in other experimental trials including vaccine trials.

Concurrent Medication:

Excluded:

• Other approved or investigational antiretroviral agents, other investigational agents, or vaccines.
• Glucocorticoids and steroid hormones.
• Dicumarol, warfarin, and other anticoagulants.
• Digitoxin.
• Valproic acid.
• Tolbutamide.
• Doxycycline.
• Chloramphenicol.
• Phenobarbital and other barbiturates.

Excluded 4 hours before or after a nevirapine dose:

• Antacids (particularly those containing calcium carbonate).
• H-2 blockers, carafate, cholestyramine resin, alcohol and alcohol-containing substances, and benzodiazepines (e.g., diazepam, triazolam).

Patients with the following prior conditions are excluded:

• History of clinically important disease other than HIV infection.

Prior Medication:

Excluded within 1 month prior to study entry:

• Any immunosuppressive, immunomodulatory, or cytotoxic treatment.

Use of drugs or alcohol sufficient to impair compliance with protocol requirements.