Urine pentamidine as an indicator of lung pentamidine in patients receiving aerosol therapy.

To determine if urine pentamidine was reflective of lung pentamidine, we compared levels of the drug in bronchoalveolar lavage fluid and simultaneously obtained urine. Thirty-one patients who were receiving aerosolized pentamidine either as treatment or as prophylaxis underwent BAL and submitted urine samples for pentamidine analysis. Pentamidine was analyzed in both phases of BAL fluid (supernatant and cell pellet) and in urine using high performance liquid chromatography. Urine results were normalized for creatinine. Patients were categorized as prophylaxis failures (active Pneumocystis carinii pneumonia on prophylaxis), electives (free from PCP on prophylaxis), treatment (daily AP in treatment doses for active PCP, or miscellaneous (single dose of AP). Levels in BAL fluid and urine varied widely over several orders of magnitude. However, for all patients, we found a highly significant relationship between BAL supernatant and urine (r = 0.97, p less than 0.0001). No statistical differences were found when comparing levels of pentamidine between failures and electives; however, the number of failures was small. We conclude that urine pentamidine is related to lung pentamidine and can be used as a clinical indicator in patients receiving aerosolized therapy.