Pharmacokinetics of mezlocillin in pleural fluid.

Mezlocillin concentrations in the pleural fluid and serum of six patients with malignant pleural effusion were determined following administration of 10 g mezlocillin over 30 minutes as a rapid infusion. Thirty minutes and eight hours after the infusion had been completed, concentrations of the active ingredient in the pleural fluid were 36.44 micrograms/ml and 112 micrograms/ml respectively; in the serum the respective values were 777.89 micrograms/ml and 44.22 micrograms/ml. The concentrations of active ingredient in the pleural fluid exceed the MIC for clinically significant pathogenic germs. The elimination half-life of mezlocillin in malignant pleural effusion is prolonged.