Treatment and prophylaxis for Pneumocystis carinii pneumonia.

Without treatment, Pneumocystis carinii pneumonitis is almost always fatal in the immunocompromised host. Here, Walter Hughes discusses proven and potential treatments, and methods of chemoprophylaxis in high-risk patients. Two drugs, pentamidine isethionate and trimethoprimsulfamethoxazole, are equally effective therapeutically - permitting the recovery of approximately 75% of patients - but the latter drug combination is preferred because of its lower toxicity and fewer adverse effects. The pneumonitis can be prevented by prophylactic administration of trimethoprim-sulfamethoxazole. Other drugs with proven efficacy or under study include Fansidar, dapsone, trimetrexate and difluoromethylornithine.