Prophylaxis with tinidazole in oral surgery. Tissue penetration and effect on the oral microflora

10 patients with odontogenic cysts were given 500 mg tinidazole orally every 12 h for infection prophylaxis before cystectomy. The administration started 48 h before operation and lasted for 7 days. Samples for assay of tinidazole were collected from blood plasma and cystic fluid during surgery. Saliva samples for microbiological studies of the normal flora were obtained before, during and after the antibiotic administration period. Mean concentrations of tinidazole in plasma and cystic fluid were 10.7 mg/l and 10.0 mg/l, respectively. The anaerobic flora was suppressed in all patients and two patients were colonized with enterobacteria, and two with fungi. No anaerobic bacterial strains resistant to tinidazole emerged during the treatment period. It is concluded that tinidazole can be administered prophylactically 48 h before oral surgery, in order to obtain maximal tissue concentration, without risk of the emergence of resistant bacterial strains or severe ecological disturbances of the oral microflora.