The Effects of Anti-HIV Drugs in HIV-Infected Patients Who Do Not Have AIDS

Inclusion Criteria Concurrent Medication: Allowed: * Chemoprophylaxis against M. tuberculosis, therapy for oral candidiasis, and short courses (up to 10 days) of acyclovir for herpes lesions. * Antibiotics as clinically indicated. * Pneumococcal vaccine and hepatitis B vaccine as medically indicated. * Regularly prescribed medications such as antipyretics, analgesics, allergy medications, antidepressants, sleep medications, oral contraceptives, or other medications deemed appropriate by the patient's primary care provider. Recommended: * PCP prophylaxis if patient's CD4 count falls below 200 cells/mm3 during the study. Concurrent Treatment: Allowed: * Alternative therapies such as vitamins and acupuncture. Patients must have: * Documented HIV infection. * At least two palpable lymph nodes above the waist. * CD4 counts \>= 350 cells/mm3 (if previously antiretroviral-naive) or \>= 250 cells/mm3 (if receiving ongoing AZT therapy). Patients with prior AZT therapy must have received a stable dose of 300-600 mg daily for 26 or more weeks. Prior Medication: Required in patients with prior ongoing therapy: * AZT at dose of 300-600 mg daily for at least 26 weeks. Exclusion Criteria Co-existing Condition: Patients with the following symptoms and conditions are excluded: * Severe malabsorption. * Current AIDS-related opportunistic infection, AIDS dementia, AIDS-wasting syndrome, or an AIDS-related malignancy other than minimal Kaposi's sarcoma disease. * Current medical problems that may interfere with the evaluation of AZT or increase the potential toxicity of AZT (e.g., significant liver disease, diabetes, significant cardiovascular disease, seizure disorders, lymphoma, acute or chronic pancreatitis, or febrile illness). * Current diagnosis of malignancy for which systemic therapy would be required during study. Concurrent Medication: Excluded: * Ganciclovir, foscarnet, chronic acyclovir, or probenecid. * Other proven or alleged antiretroviral or anti-HIV drugs. * Biologic response modifiers. * Valproic acid. * Systemic cytotoxic chemotherapy. * Steroids. Concurrent Treatment: Excluded: * Radiation therapy. Patients with the following prior conditions are excluded: * Prior AIDS-related opportunistic infection, AIDS dementia, AIDS-wasting syndrome, or an AIDS-related malignancy other than minimal Kaposi's sarcoma disease. * History of medical problems that may interfere with the evaluation of AZT or increase the potential toxicity of AZT (e.g., significant liver disease, diabetes, significant cardiovascular disease, seizure disorders, lymphoma, acute or chronic pancreatitis, or febrile illness). * History of peripheral neuropathy (patients with prior AZT treatment only). Prior Medication: Excluded: * Prior ddI therapy. * Less than 26 weeks of prior AZT (in patients with ongoing AZT therapy only). * Ganciclovir, foscarnet, chronic acyclovir, or probenecid. * Cytotoxic chemotherapy within 1 month prior to study entry. * Acute therapy for an infection or other medical illness within 14 days prior to study entry. History of alcohol abuse (patients with prior AZT treatment).