Albendazole inhibits Pneumocystis carinii proliferation in inoculated immunosuppressed mice.

Albendazole, a benzimidazole derivative widely used for treating helminth infections, was successfully used to treat and prevent development of Pneumocystis carinii pneumonia in transtracheally inoculated immunosuppressed mice. For treatment, 3 weeks postinoculation, albendazole at 300 and 600 mg/kg of body weight per day was administered in food for 3 weeks. For prophylaxis, albendazole was begun on the same day as inoculation at 300 mg/kg/day for 7 days, and then the dose was reduced to 150 mg/kg/day for 35 additional days. With these regimens, albendazole was effective both for treatment and prophylaxis. Both dexamethasone-immunosuppressed and L3T4+ monoclonal antibody-immunosuppressed mouse models were used, and albendazole inhibited P. carinii infection in both.