A Multicenter, Double Blind, Comparative Study of Zidovudine Alone Versus Zidovudine and Acyclovir as Treatment for HIV-Infected Patients With CD4+ Counts Less Than 200 Cells/mm3

Inclusion Criteria Concurrent Medication: Allowed: * Methadone maintenance. Therapies available through expanded access or treatment IND programs unless specifically excluded. * Allowed within 30 days of study entry: * Systemic steroids only if given for treatment of Pneumocystis carinii pneumonia. * Recommended: * PCP prophylaxis. Patient must have: * Recovered from first episode of histologically proven Pneumocystis carinii pneumonia (PCP) or microbiologically proven AIDS-defining opportunistic infection as defined in Centers for Disease Control HIV classification group IV. * C-1. * Study entry must be within 120 days of AIDS-defining diagnosis. * Written documentation of positive antibody to HIV by any federally licensed ELISA test kit. This test should be confirmed by another method, for example, Western blot, radioimmunoassay (RIA), HIV culture. * Patients cannot be transfusion dependent (requiring blood transfusion more than once per month). The last transfusion must be \> 2 weeks before entry. * AMENDED 90-08-27 to include HIV positive patients with CD4+ count \< 200 cells/mm3. Prior Medication: Allowed: * Zidovudine (AZT) for \< 365 days prior to study entry. Exclusion Criteria Co-existing Condition: Patients with the following are excluded: * Symptomatic visceral or progressive Kaposi's sarcoma (KS) (defined by \> 10 new lesions in the 30 days prior to entry). * Other concurrent neoplasms other than basal cell carcinoma of skin (patients who have been in complete remission for 1 year for a malignancy may be enrolled). * Malabsorption as defined by persistent diarrhea \> 6 stools/day for \> 4 weeks. Patients whose sole AIDS-defining condition is constitutional disease as defined in CDC's HIV group IV-A or neurologic disease as defined in CDC's HIV group IV-B or AIDS-associated malignancies as defined in CDC's HIV group IV-C. Concurrent Medication: Excluded: * Acyclovir (ACV) prophylaxis or frequent (\> once per month) repeated courses of ACV therapy for herpes simplex virus infection. * Any concomitant medicine unless required. * Systemic therapy/prophylaxis/maintenance for AIDS-defining opportunistic infection other than prophylaxis for Pneumocystis carinii pneumonia (PCP). * Acetaminophen for \> 72 hours. Cimetidine. * Flurazepam. * Indomethacin. * Ranitidine. * Probenecid (if receiving AZT). * Rifampin. * Rifampin-related drugs. Patients with the following are excluded: * Active opportunistic infections. * Symptomatic visceral or progressive Kaposi's sarcoma (KS) (defined by \> 10 new lesions in the 30 days prior to entry). * Other concurrent neoplasms other than basal cell carcinoma of skin (patients who have been in complete remission for 1 year for a malignancy may be enrolled). * Malabsorption as defined by persistent diarrhea \> 6 stools/day for \> 4 weeks. * Patients whose sole AIDS-defining condition is constitutional disease as defined in CDC's HIV group IV-A or neurologic disease as defined in CDC's HIV group IV-B or AIDS-associated malignancies as defined in CDC's HIV group IV-C. Prior Medication: Excluded: * Zidovudine (AZT) for \> 365 days prior to study entry. * Excluded within 14 days of study entry: * Systemic acyclovir (ACV) therapy. * Excluded within 30 days of study entry: * Antiretroviral therapy (other than AZT per above). * Immunomodulating agents. * Biologic response modifiers. Excluded within 60 days of study entry: * Ribavirin. Prior Treatment: Excluded within 30 days of study entry: * Cytotoxic chemotherapy or radiation therapy for Kaposi's sarcoma. Active substance abuse that would impair compliance with study procedure.