Metronidazole: two or three times daily--a comparative controlled clinical trial of the efficacy of two different dosing schedules of metronidazole for chemoprophylaxis following third molar surgery

Abstract

Metronidazole, used for prevention and treatment of infections in oral and maxillofacial surgery is frequently prescribed three times daily, but research into its pharmacokinetics has shown that a twelve hourly dosage regimen achieves and maintains therapeutic serum concentrations. No clinical data is available to support this and consequently a single blind, prospective, randomised trial was carried out to compare rates of postoperative infection following mandibular third molar excision under general anaesthesia. Sixty-two patients were randomly allocated to receive either 400 mg of metronidazole twice or three times daily for 5 days and all were assessed by the same surgeon for postoperative infection 7 days later. There was no statistically significant difference between rates of infection in either group and of potential side effects only nausea occurred statistically more frequently in the three times daily group. It would appear that a 12-hourly dose interval of metronidazole is no different from an 8-hourly dose interval, in prevention of local wound infection following minor oral surgery.