Chronic pentamidine aerosol prophylaxis does not induce QT prolongation

Intravenous administration of pentamidine is known to cause long-QT syndrome (Torsade de pointes tachycardias and large QT prolongation) in rare cases and to cause small QT prolongation regularly. A similar pattern is seen with other drugs known to cause a long-QT syndrome. Pentamidine aerosol prophylaxis is commonly used to prevent Pneumocystis carinii pneumonia in HIV-infected persons. The goal of this study was to clarify whether pentamidine aerosol prophylaxis induces QT prolongation. We examined 100 patients receiving pentamidine aerosol prophylaxis at a rather high dose (300 mg biweekly) for at least 1 month (range 1-24) by determining the QT interval corrected for heart rate (QTc), blind for treatment. In a cross-sectional study, QTc was not different in 50 HIV-infected patients with chronic pentamidine aerosol prophylaxis (413 ms), 50 similar HIV-infected patients without pentamidine (407 ms), and 50 similar patients without HIV-infection and without pentamidine (407 ms). In a longitudinal study in another 50 HIV-infected patients, QTc was the same before (414 ms) and on long-term (median 9-month) pentamidine aerosol prophylaxis (414 ms). In contrast to the case with intravenous pentamidine, we found no QT prolongation and thereby no risk of long-QT syndrome with pentamidine aerosol prophylaxis.