Norfloxacin for prevention of bacterial infections in granulocytopenic patients.

The efficacy and safety of norfloxacin were compared with those of placebo, vancomycin-polymyxin, and trimethoprim-sulfamethoxazole (TMP/SMX) for prophylaxis of bacterial infections in granulocytopenic patients. The study results showed that norfloxacin treatment, which was well tolerated and not associated with any serious systemic adverse effects, prevented acquisition of gram-negative bacillary organisms. Fewer norfloxacin-treated patients (38 of 108 patients, or 35 percent) experienced microbiologically documented infections compared with patients receiving placebo (27 of 40 patients, or 68 percent), vancomycin-polymyxin (16 of 30 patients, or 53 percent), or TMP/SMX (14 of 28 patients, or 50 percent). Gram-negative bacteremia developed in five of 108 norfloxacin-treated patients (5 percent), compared with 17 of 40 placebo-treated patients (43 percent), five of 30 treated with vancomycin-polymyxin (17 percent), and one of 28 patients treated with TMP/SMX (4 percent). The incidence of gram-positive bacteremia was similar in all study groups and was not affected by norfloxacin or any other oral prophylactic antibiotics. These results suggest that norfloxacin is both safe and effective for the prevention of serious gram-negative bacillary infections in granulocytopenic patients. More effective prophylaxis of gram-positive bacterial infections, however, is needed.