Concentration of Penicillin and Tetracycline in Maxillary Sinus Secretion after a Single Dose

Abstract

17 patients with maxillary sinusitis were given a single dose of either penicillin only, or penicillin in combination with tetracycline. Samples of sinus secretions were aspirated at intervals and, simultaneously, a blood sample was obtained. The antibiotic concentrations were determined by an agar diffusion method using paper discs as diffusion centres. Neither penicillin nor tetracycline showed any uniform relationship between the concentrations in serum and secretion after a single dose. In 8 of the 20 secretions, the concentrations of penicillin exceeded the upper limit of minimal inhibitory concentration (MIC) for bacterial sensitivity group 1, i.e. 0.25 μg/ml. A rise in the serum concentration of penicillin was associated with a greater chance of attaining this value. The tetracycline concentration exceeded 1.0 μg/ml (the upper limit of MIC in group 1) in only 3 of 16 secretions. In 2 patients receiving repeated doses tetracycline accumulated in the secretions resulting in concentrations about equal to, or above, the maximal serum concentration. Pencillin and tetracycline concentrations in sinus secretions will remain for at least 6–8 hours.