Effect of lomefloxacin on the normal oral and intestinal microflora.

Ten healthy volunteers received 400 mg of lomefloxacin orally once daily for seven days. Saliva and faecal samples were collected on days 0, 2, 4, 7, 9, 11, 14 and 21 to investigate the effect of lomefloxacin on the normal oral and intestinal microflora. The mean concentration of lomefloxacin in faeces on day 7 was 203 mg/kg, while saliva levels were low, less than 0.6 mg/l in nine of ten volunteers. Aerobic gram-negative microorganisms were almost completely eradicated, while aerobic gram-positive and anaerobic microorganisms were virtually unaffected by the lomefloxacin administration. Two weeks after lomefloxacin was discontinued, the oral and intestinal microflora had returned to normal levels.