Evaluation of spiramycin as a therapeutic agent for elimination of nasopharyngeal pathogens. Possible use of spiramycin for middle ear infections and for gonococcal and meningococcal nasopharyngeal carriage.

Varying doses of spiramycin were administered orally to healthy volunteers, and concentrations in serum and saliva were determined. The absorption of the drug was not significantly influenced by concomitant food intake. Saliva peak concentrations were 1.3--4.8 times higher than peak concentrations in serum. The elimination half life was 2--3 h in serum, and 4--8 h in saliva. Accumulation of the drug was seen in saliva but not in serum. The possible effect of spiramycin in eliminating bacteria from the nasopharynx was evaluated in vitro by comparing the spiramycin saliva concentrations with the MICs of bacteria known to establish themselves in the nasopharynx. At a concentration of 1.2 microgram/ml, spiramycin inhibited all investigated strains of group A streptococci, pneumococci and Branhamella catarrhalis, and at 2.4 microgram/ml all investigated gonococci. Concentrations of 19 and 38 microgram/ml, respectively, were required to inhibit all meningococci and Haemophilus influenzae. Following administration of 1.5 g spiramycin as a single daily dose for 3 days, the mean concentration in saliva reached or surpassed the MIC values of streptococci, pneumococci and Branhamella for 45 h, and of gonococci for 25 h. The possible use of spiramycin for prevention of relapses in acute otitis media and in treatment of serous otitis media is discussed, as well as the possible use of the drug in gonococcal and meningococcal nasopharyngeal carriage.