PHARMACOKINETICS OF AZITHROMYCIN IN PEDIATRIC-PATIENTS WITH ACUTE OTITIS-MEDIA

The objective of our study was to characterize the pharmacokinetics of azithromycin after the oral administration of multiple doses in suspe nsion to children with acute otitis media. Thirteen children (ranging in age from 7.5 months to 5 years) received a single oral dose of 10 m g of azithromycin per kg of body weight on day 1 followed by single da ily doses of 5 mg/kg on days 2 to 5. Each child fasted overnight befor e receiving the final dose on day 5. Multiple blood samples were colle cted after the last dose. Concentrations of azithromycin in serum were measured by a specific high-performance liquid chromatography-mass sp ectrometry method. The means and standard deviations for the maximum c oncentration of azithromycin in serum, the time to maximum concentrati on of azithromycin in serum, the area under the concentration-time cur ve (from 0 to 24 h), and the elimination half-life were 224 +/- 120 ng /ml, 1.8 +/- 0.4 h, 1,841 +/- 651 ng . h/ml, and 31.6 +/- 6.6 h, respe ctively. Concentrations in serum (means +/- standard deviations) at 0 h (predose) and at 24, 48, and 72 h after the final dose were 51 +/- 2 6, 47 +/- 21, 27 +/- 17, and 17 +/- 13 ng/ml, respectively. Thus, the once-daily administration of azithromycin resulted in sustained system ic exposure to the drug. The drug dosage regimen used in this study sh ould lead to tissue drug concentrations exceeding the MICs for common pathogens.