AZITHROMYCIN CONCENTRATIONS AND MICROBIOLOGY OF TONSILS DURING WEEKLYMEDICATION IN PATIENTS WITH RECURRENT TONSILLITIS

This study was performed in order to assess whether 500mg of azithromy cin given orally once per week could produce tonsil tissue concentrati ons above minimum inhibitory concentrations for key target pathogens i n patients with recurrent tonsillitis. For the measurement of tissue c oncentrations an automated solid phase extraction (SPE) method for cle aning the tissue extracts was developed. Concomitantly, the influence of this treatment on the microbiological flora of the tonsillar surfac e was monitored. The mean concentration of azithromycin in the tonsill ar tissue was 1.8 mu g/g (0.4 mu g/g to 5.1 mu g/g), i.e. therapeutic concentrations of azithromycin were found in most tonsils 1 week after medication. The validated SPE method developed provided a clean extra ct for high performance liquid chromatographic determination of azithr omycin. The surface microbiology of the tonsils at surgery showed the usual pathogens in most patients. In conclusion, therapeutic levels of azithromycin were present in tonsil tissue during weekly medication w ith minimal influence on surface microbiology. A placebo-controlled, d ouble-blind study of long-term treatment is in progress.