A controlled study of inhaled pentamidine for primary prevention of Pneumocystis carinii pneumonia

Use of low-dose trimethoprim-sulfamethoxazole thrice weekly for primary and secondary prophylaxis of Pneumocystis carinii pneumonia in human immunodeficiency virus-infected patients

We conducted an open prospective clinical trial to evaluate the efficacy and toxicity of trimethoprim-sulfamethoxazole given as one double-strength tablet thrice weekly for primary and secondary prophylaxis of Pneumocystis carinii pneumonia (PCP) in human immunodeficiency virus-infected (HIV+) patients. A total of 104 HIV+ patients were evaluated, with 74 being in the primary prophylaxis group and 30 being in the secondary prophylaxis group. All except six patients received concomitant zidovudine; five patients on primary prophylaxis and one patient on secondary prophylaxis refused zidovudine. There were 70 patients evaluated for the efficacy of primary prophylaxis. The mean CD4 count was 124.4 +/- 110.1 cells per microliter. The mean follow-up time was 11.8 +/- 5.8 months (median, 12 months; range, 1 to 32 months). Two noncompliant patients developed PCP after 1 and 3 months of chemoprophylaxis. The failure rate (under the intention to treat principle) was 2 of 70 patients (2.9%; 95% confidence interval, 0.35 to 10%), or 1 per 413 patient-months of observation. There were 27 patients evaluated for the efficacy of secondary prophylaxis. The mean follow-up time was 12.4 +/- 7.2 months (median, 11 months; range, 1 to 29 months). Two patients, one of whom was noncompliant, were treatment failures, developing PCP after 14 and 15 months of chemoprophylaxis; this gave a failure rate of 2 of 27 patients (7.4%; 95% confidence interval, 0.9 to 24.3%), or 1 per 167 patient-months of observation. Adverse reactions sufficient to permanently terminate therapy occurred in 9 of 104 patients (8.7%; 95% confidence interval, 4 to 15.7%) overall. The serum trimethoprim, sulfamethoxazole, and N4-acetyl-sulfamethoxazole concentrations measured by high-pressure liquid chromatography were uniformly low. One double-strength tablet of trimethoprim-sulfamethoxazole taken weekly on Monday, Wednesday, and Friday appeared to be well tolerated and efficacious for the prophylaxis of PCP in HIV+ patients at high risk and deserves further investigation.

Treatment and prophylaxis of Pneumocystis carinii pneumonia in AIDS patients

Pneumocystis carinii pneumonia (PCP) is seen in people with a defect in cell-mediated immunity. Today the most common cause for this is the Acquired Immunodeficiency Syndrome (AIDS). There have been some remarkable advances recently in the development of new drug regimens to combat this otherwise fatal infection. Although cotrimoxazole (trimethoprim-sulfamethoxazole) is still the drug of first choice it cannot be tolerated by a significant proportion of patients, and therapies such as pentamidine (pentamidine-isethionate) [intravenous or nebulised], dapsone-trimethoprim, eflornithine (DFMO; difluoromethylornithine), trimetrexate, and clindamycin-primaquine are finding therapeutic niches. The major advantage in these other agents is not improved efficacy but different toxicity profiles, enabling therapy to be most appropriately tailored to individual patients' conditions. Although the majority of patients should now survive an attack of PCP, relapses will occur if prophylaxis is not used. There is also the capacity to predict accurately which patients are at risk for this pneumonia and prevent it through the use of chemoprophylaxis. These advances in the treatment and prevention of PCP, together with anti-retroviral therapy, mean that this is an area of AIDS management that has resulted in improved long term survival.