Norfloxacin: a quinoline antibiotic.

Norfloxacin is a quinoline (quinolinecarboxylic acid) that should prove successful in treating infections that currently require hospitalization and intravenous antibiotics. Although a nalidixic acid derivative, it possesses greater antibacterial activity against gram-positive and gram-negative bacteria. Compared with other antimicrobial agents, norfloxacin is more potent than the aminoglycosides, first-, second-, and third-generation cephalosporins, tetracycline, trimethoprim-sulfamethoxazole, carbenicillin, piperacillin, nalidixic acid, oxolinic acid, cinoxacin, and enoxacin. In the clinical studies to date, the side effects of norfloxacin have been minimal, but include nausea, vomiting, anorexia, dizziness, headache, drowsiness, depression, and a bitter taste in the mouth. In studies with more than 4000 patients, the incidence of side effects ranged from 3.9 to 4.7 percent, with most appearing by the second day of therapy.