Aerosolized pentamidine and Pneumocystis carinii pneumonia: patient compliance and outcomes

OBJECTIVE: The study objectives were to compare compliance between every-two-week and every-four-week aerosolized pentamidine regimens, and to determine if patients who were more compliant with the use of aerosolized pentamidine were at decreased risk for developing Pneumocystis carinii pneumonia (PCP). DESIGN: Nonrandomized observational study of patients receiving aerosolized pentamidine for PCP prophylaxis using the hospital pharmacy computer system to document aerosolized pentamidine use and compliance, and the Patient Administration Division's computer to document cases of PCP. SETTING: Tertiary care, US Army medical center. PATIENTS: All patients who were prescribed aerosolized pentamidine (60 mg every two weeks, 300 mg every four weeks, or both) over a 3.5-year period. MAIN OUTCOME MEASURES: Mean percent compliance was determined and compared between every-two-week and every-four-week regimens. The relationship between compliance and cases of PCP as determined using nonparametric statistics. RESULTS: Patients (n = 146) who were prescribed aerosolized pentamidine 60 mg every two weeks were more compliant (p = 0.006) than those prescribed 300 mg every four weeks. In addition, those patients who initially received the 60-mg regimen and were switched to the 300-mg regimen were more compliant when taking the 60-mg dose (p = 0.027). There was no association between compliance with either regimen and cases of PCP. Compliance generally was poor with both regimens. CONCLUSIONS: Patients on every-two-week regimens of aerosolized pentamidine were more compliant than those on every-four-week regimens. However, regardless of compliance, some patients failed aerosolized pentamidine over the 3.5-year period. Other agents that lend themselves to compliance may be more appropriate for PCP prophylaxis than aerosolized pentamidine.