To evaluate and compare the safety, tolerability, and efficacy of biweekly administration of aerosol pentamidine versus placebo when used as a prophylactic agent in patients who have recovered from their first episode of AIDS-associated Pneumocystis carinii pneumonia (PCP).

Inclusion Criteria

Concurrent Medication:

Allowed:

• Zidovudine (AZT). If AZT is started during the study, patients must have received = or > 15 days of aerosol pentamidine before beginning AZT.

Prior Medication:

Allowed:

• Zidovudine (AZT). If AZT began prior to study entry, patients must have received = or > 15 days of AZT before beginning aerosol pentamidine.

Exclusion Criteria

Co-existing Condition:

Patients with the following are excluded:

• Requiring ongoing active therapy for an opportunistic infection (O.I.) at time of entry or those with either of the following AIDS-defining O.I.'s prior to entry:
• Toxoplasmosis.
• Cryptococcosis.
• Transfusion dependent (requiring blood transfusion more than once per month). The last transfusion cannot have been given within 7 days of study entry.
• Pulmonary Kaposi's sarcoma (KS).
• Uncontrolled asthma.
• Active therapy for tuberculosis.

Patients with the following are excluded:

• Requiring ongoing active therapy for an opportunistic infection (O.I.) at time of entry or those with either of the following AIDS-defining O.I.'s prior to entry:
• Toxoplasmosis.
• Cryptococcosis.
• Transfusion dependent (requiring blood transfusion more than once per month). The last transfusion cannot have been given within 7 days of study entry.
• Pulmonary Kaposi's sarcoma (KS).
• Uncontrolled asthma.

Prior Medication:

Excluded within 30 days of study entry:

• Antiretroviral agents other than zidovudine (AZT).
• Immunomodulating agents.
• Corticosteroids.

Active therapy for tuberculosis.

Patients must:

• Have AIDS and recovered from their first episode of Pneumocystis carinii pneumonia (PCP).
• Be at least 2 weeks and no more than 24 weeks status post therapy for acute PCP.
• Have positive antibody to HIV by a Government-approved ELISA test kit, or confirmed Western blot test.
• Adequate pulmonary function (vital capacity = or > 80 percent of predicted; forced expiratory volume (FEV), 1 s = or > 65 percent of total FEV; and corrected pulmonary diffusion capacity > 60 percent of predicted).
• Free of acute medical problems.

Active substance abuse.