Piperacillin-tazobactam versus imipenem-cilastatin for treatment of intra-abdominal infections

In order to compare the clinical and microbiological efficacies and safety of piperacillin plus tazobactam with those of imipenem plus cilastatin, 134 patients with intra-abdominal infections (73 patients with appendicitis) participated in an open randomized comparative multicenter trial. A total of 40 men and 29 women (mean age, 53 years; age range, 18 to 92 years) were enrolled in the piperacillin-tazobactam group and 40 men and 25 women (mean age, 54 years; age range, 16 to 91 years) were enrolled in the imipenem-cilastatin group. The patients received either piperacillin (4 g) and tazobactam (500 mg) every 8 h or imipenem and cilastatin (500 mg each) every 8 h. Both regimens were given by intravenous infusion. A total of 113 patients were clinically evaluable. Of 55 patients who received piperacillin-tazobactam, 50 were clinically cured, while 40 of 58 patients in the imipenem-cilastatin group were clinically cured. The differences were significant (Wilcoxon test; P = 0.005). There were 4 failures or relapses in the piperacillin-tazobactam group and 18 failures or relapses in the imipenem-cilastatin group. The microorganisms isolated were eradicated in similar proportions in the two patient groups. Adverse reactions, mainly gastrointestinal disturbances and nausea, were noted in 13 patients who received piperacillin-tazobactam and in 14 patients who received imipenem-cilastatin. Results of the present study show that piperacillin-tazobactam is effective and safe for the treatment of intra-abdominal infections.