Randomized comparison of piperacillin/tazobactam versus imipenem/cilastatin in the treatment of patients with intra-abdominal infection

Abstract

OBJECTIVES: Treatment of intra-abdominal infections remains a challenge because of their polymicrobial nature and associated mortality risk. Broad-spectrum empiric coverage is usually required. This randomized study compared the efficacy and safety of intravenous piperacillin/tazobactam with those of intravenous imipenem/cilastatin in the treatment of 293 hospitalized patients with intra-abdominal infection. METHODS: A total of 149 patients received piperacillin/tazobactam 4 g/500 mg every 8 hours, and 144 patients received imipenem/cilastatin 500 mg/500 mg every 6 hours. Efficacy was evaluated by clinical and bacteriological response. Safety was evaluated by analysis of adverse events and physical and laboratory examinations. RESULTS: Clinical and bacteriological responses in both evaluable treatment groups were equivalent. The clinical success was 97% (108/111) for piperacillin/tazobactam and 97% (100/103) for imipenem/cilastatin. Bacteriological success was 97% (67/69) for piperacillin/tazobactam and 95% (61/64) for imipenem/cilastatin. The most common pathogens were Escherichia coli, Klebsiella pneumoniae, Enterobacter species and Pseudomonas aeruginosa. The frequencies of treatment-related adverse events were similar (16 with piperacillin/tazobactam and 19 with imipenem/cilastatin). CONCLUSIONS: These results suggest that the safety and efficacy of piperacillin/tazobactam administered every 8 hours are equivalent to those of imipenem/cilastatin administered every 6 hours for the treatment of intra-abdominal infections.