A Double-Blind, Placebo-Controlled Trial of Albendazole in HIV-Positive Patients With Intestinal Microsporidiosis

Inclusion Criteria Concurrent Medication: Required: * If coincident enteric pathogens that are not eradicable (i.e., Mycobacterium avium complex) are detected, they should be treated appropriately and the patient must be on a stable regimen of therapy for at least two weeks. Allowed: * Patients taking antidiarrheal medications must be on a stable regimen for at least seven days prior to randomization. * Patients taking other concomitant medications, including antiretrovirals, must be on a stable regimen for two weeks prior to randomization. Patients must have: * HIV positive status. Written documentation (for example, patient's chart) of HIV diagnosis is acceptable in lieu of repeat testing. Confirmation by Western blot is not necessary. * Biopsy-proven microsporidiosis of the fourth portion of the duodenum or proximal jejunum within 90 days before randomization. * Average of \> 3 liquid bowel movements per day over 7 consecutive days immediately prior to randomization, with an average volume \> 500 ml per day over three or more consecutive days immediately prior to randomization, as documented by data collected in a daily diary. NOTE: * Patients receiving antidiarrheal therapy must meet these criteria despite such therapy. * History of an average of \> 3 liquid bowel movements per day for three additional weeks immediately preceding the 7-day period described above (for a total of four weeks), as documented in the patient's chart. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Grade 4 neutropenia. * Decompensated liver disease. * Positive toxin analysis for C. difficile. * Positive microscopic examination for Giardia lamblia, Entamoeba histolytica, and Isospora belli. * Positive on culture for Shigella, Salmonella, Yersinia and Campylobacter. * Positive fluorescent antibody test for Cryptosporidium. * Evidence of CMV on small bowel biopsy, flexible sigmoidoscopic or colonoscopic biopsies within 90 days of randomization. * Any other condition that, in the opinion of the investigator, makes the patient unsuitable for study entry. Patients with the following prior conditions are excluded: Hypersensitivity to albendazole. Prior Medication: Excluded: * Use of potential antiprotozoal drugs, e.g., mebendazole or metronidazole, within one week prior to enrollment. * Receipt of albendazole during the one month prior to enrollment.