Pentamidine-associated nephrotoxicity and hyperkalemia in patients with AIDS

The incidences of pentamidine-associated nephrotoxicity and hyperkalemia were determined from a retrospective review of records in AIDS patients using standard definitions for both toxicities. There were 37 patients, mean age 35.6 +/- 7.7 years and mean initial creatinine clearance (Clcr) 96 mL/min (1.6 mL/s). The mean pentamidine dose was 255 +/- 60 mg/d (3.87 +/- 0.33 mg/kg/d). The mean total dose was 2900 +/- 1600 mg given over 11.6 +/- 5.9 days (range 3-21 d). In 28 patients who were nephrotoxic (8 mild, 6 moderate, 14 severe), 27 episodes were possibly or probably pentamidine-associated. Total dose and days to nephrotoxicity onset were 1570 +/- 710 mg and 6.4 +/- 2.8 days (range 2-15 d), respectively. Nine patients became hyperkalemic (one required countermeasures) and all cases were pentamidine-associated. Total dose and days to hyperkalemia onset were 2510 +/- 1460 mg and 9.2 +/- 4.9 days (range 3-16 d), respectively. Mean baseline potassium increased and Clcr decreased significantly during therapy (from 4.2 to 4.9 mEq/L and from 96 to 70 mL/min, respectively). No correlation between nephrotoxicity or hyperkalemia and initial renal function was found, but significant correlations were found between the total pentamidine dose or duration and the percent of renal function remaining. AIDS patients have a high incidence of pentamidine-associated nephrotoxicity (up to 73 percent) and hyperkalemia (24 percent) with a trend to earlier onset of the former.