A prospective, randomized, double-blind study of single high dose versus multiple standard dose gentamicin both in combination with metronidazole forcolorectal surgical prophylaxis

Single, high dose regimens of gentamicin plus metronidazole for colorectal surgical prophylaxis have not been adequately studied. Patients received si ngle high dose gentamicin (4.5 mg/kg) plus metronidazole (500mg) preoperati vely or multiple standard dose gentamicin (1.5 mg/kg) plus metronidazole (5 00 mg) preoperatively and every 8h for 24h postoperatively. The deep surgic al site infection (SSI) rates were 8.1% (6/74) and 6.9% (5/72) in the singl e high dose and multiple standard dose groups, respectively (P=0.94). There was a trend towards fewer superficial SSIs in the single high dose group w ith infection rates of 18.9% (14/74) vs. 30.6% (22/72) (P=0.05). Diabetes m ellitus (odds ratio = 7.04) and surgery duration of longer than 3h (odds ra tio = 5.46) were independent risk factors for the development of SSIs. A su bset analysis of prolonged operations found significantly fewer superficial SSIs in the single high dose group than in the multiple standard dose grou p with rates of 22.2% (6/27) vs. 55% (11/20), respectively (P=0.021). Singl e high dose gentamicin plus metronidazole preoperatively was at least as ef fective as the multiple standard dose regimen and may be more effective for prolonged operations. (C) 2000 The Hospital Infection Society.