Concentration of Antibiotics in Sinus Secretions

Abstract

Patients with acute maxillary sinusitis with secretion were treated by doxycycline and spiramycin. Doxycycline was given for nine days, 200 mg initially followed by a single daily dose of 100 mg. Spiramycin was given for 10 days, 1.5 g twice a day. The concentration of the antibiotics was determined in 149 samples of sinus secretion, aspirated or irrigated, from 58 patients by means of the bacterium inhibitory capacity of the antibiotic. The concentrations of the antibiotics were measured biologically on blood agar plates of standardized thickness, seeded with appropriate bacterial strains. The concentration in general was well above the MIC for the bacteria found. There was a statistically significant increase in spiramycin concentration with duration of therapy. However, the concentration in general showed very varying values for both antibiotics without any correlation to such parameters as age, radiological finding, appearance of the sinus content and interval from the last antibiotic dose. The reason for this is discussed.