Inclusion Criteria

Concurrent Medication:

Allowed:

• Zidovudine.
• Antidiarrheal medication with imodium or paregoric only.

Patients must have:

• HIV infection.
• Intestinal cryptosporidiosis proven by stool microscopy on at least two occasions prior to study enrollment.
• Life expectancy of at least 2 weeks by clinical assessment. In states where the legal age of consent for medical procedures is 21 years, patients below the age of 21 must have consent of parent or guardian.

Prior Medication:

Allowed:

• Zidovudine.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms and conditions are excluded:

• Known hypersensitivity or significant intolerance to macrolide antibiotics.
• Marked abnormalities of liver or renal function.
• Causes for diarrhea other than, or in addition to, cryptosporidiosis.
• Inability to receive oral medication.

Concurrent Medication:

Excluded:

• Cancer chemotherapy (including therapy for Kaposi's sarcoma).
• Any drug or biologic preparation (e.g., bovine colostrum, paromomycin, spiramycin, somatostatin) with possible anticryptosporidial activity.
• Immunostimulant or lymphocyte replacement therapy.

Prior Medication:

Excluded:

• Another investigational drug within 7 days prior to study enrollment (investigational medications available through a treatment IND will be allowed with the approval of the sponsor, the treatment IND sponsor, and the Pfizer clinical monitor).
• Immunostimulant or lymphocyte replacement therapy.
• Cancer chemotherapy (including therapy for Kaposi's sarcoma).

Not expected to comply with the requirements of the protocol, in the opinion of the investigator.