The Safety and Effectiveness of Nevirapine and Zidovudine, Given Separately and Together, in HIV-1 Infected Patients Who Have No Symptoms of the Disease

Inclusion Criteria Concurrent Medication: Allowed: * PCP prophylaxis (trimethoprim-sulfamethoxazole, dapsone, or aerosolized pentamidine), at the discretion of the investigator. * Antifungal prophylaxis with oral fluconazole or ketoconazole. * Antiviral prophylaxis for herpes simplex virus with \<= 1000 mg/day oral acyclovir. * Dilantin for prevention and treatment of seizures. Patients must have: * Asymptomatic HIV-1 infection, with positive serum antibody to HIV-1 as determined by ELISA or Western blot. * CD4 count 200-500 cells/mm3 within 4-28 days prior to study entry. * No conditions indicative of AIDS. * None of the constitutional symptoms that are specifically excluded. * Prior AZT for 3-24 months (amended 04/04/94) immediately prior to study entry (Part I) OR no prior AZT (Part II). * Consent of parent or guardian if less than 18 years of age. NOTE: * Co-enrollment in a protocol involving another investigational drug or biologic is not permitted. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Malignancy other than limited cutaneous basal cell carcinoma. * Psychiatric condition sufficient to impair compliance with protocol requirements. Concurrent Medication: Excluded: * Investigational drugs other than study drugs. * Systemic glucocorticoids and steroid hormones. * Dicumarol, warfarin, and other anticoagulant medications. * Cimetidine. * Tolbutamide. * Doxycycline. * Chloramphenicol. * Phenobarbital and other barbiturates. * Foscarnet. * Erythromycin. * Amoxicillin-clavulanate (Augmentin). * Ticarcillin clavulanate (Timentin). * Biologic response modifiers (alpha interferon, IL-2, immune modulators). Patients with the following condition are excluded: History of other clinically important disease (i.e., one that precludes participation in the study). Prior Medication: Excluded: * Antiretroviral medications other than AZT. Excluded within 4 weeks prior to study entry: * Immunosuppressive or cytotoxic drugs or other experimental drugs. * Systemic glucocorticoids and steroid hormones. * Dicumarol, warfarin, and other anticoagulant medications. * Cimetidine. * Tolbutamide. * Doxycycline. * Chloramphenicol. * Phenobarbital and other barbiturates. * Foscarnet. * Erythromycin. * Amoxicillin-clavulanate (Augmentin). * Ticarcillin clavulanate (Timentin). * Biologic response modifiers (alpha interferon, IL-2, immune modulators). Required (for patients in Part I): * Prior AZT at 500-600 mg daily for at least 3 months but not more than 24 months immediately prior to study entry. Chronic use of alcohol or drugs sufficient to impair compliance with protocol requirements.