[Pharmacokinetics of mezlocillin in bronchial secretions (author's transl)].

This study was designed to measure the penetration of mezlocillin into respiratory secretions taken from tracheostomized patients admitted to an intensive care unit. In these patients admitted to an intensive care unit. In these patients, samples can be taken at set intervals. Eighteen patients were divided into two groups, one group received a single i.v. dose of 5 g. mezlocillin and the other a one day treatment with eight-hourly infusions of 5 g mezlocillin, samples being taken after the fourth infusion. Antibiotic concentrations were measured in simultaneous samples of serum and bronchial secretions by an agar diffusion method. The results showed considerable penetration of mezlocillin into bronchial secretions. Two hours after the end of the infusion, the peak of bronchial mezlocillin concentrations varied from 10 to more than 20 micrograms/ml. The kinetics of bronchial levels exhibited slow elimination, with still measurable levels at the sixth hour (1.5 to 3 micrograms/ml). Important individual variations were seen in patients with different clinical conditions (respiratory insufficiency, acute intoxication in forced diuresis). There was no difference between the two groups of patients, which showed that no cumulation took place. It is concluded that the passage of mezlocillin in the human respiratory tract results in high bronchial concentrations which are bactericidal to most species of Enterobacteriaceae.