[Ceftazidime absorption into bronchial secretions in mucoviscidosis patients]

Penetration of ceftazidime into bronchial secretions was studied in 23 patients, of which 18 had cystic fibrosis. Ceftazidime was used as the single drug for treating exacerbations caused by Pseudomonas aeruginosa. Dosage was 6 g/1.73 m2/day divided into three intravenous injections for 14 to 21 days. Bronchial secretion samples were obtained by fiber-optic bronchoscopy or physical therapy. Serum and bronchial secretion ceftazidime concentrations were assayed using a microbiological method. Ceftazidime concentrations in both media were lower in children than in adults : elimination half-life is shorter (1.7 h against 2.45 h in adults), extravascular distribution is faster, with earlier (1 h against 2 h in adults) achievement of the peak bronchial secretion concentration (2 micrograms/ml). The ratio of bronchial secretion concentration to concomitant serum concentration did not exceed 5% at the time of peak bronchial concentration. These results suggest that in cystic fibrosis patients, the faster and lower bronchial penetration of ceftazidime may be due to faster elimination as compared to adults. Although transient elimination of Pseudomonas aeruginosa was achieved in 12 study patients, our findings support the use of higher dosages or alternative administration modalities designed to increase in situ ceftazidime concentrations.