THE CANADIAN C LINICAL TRIALS G ROUPLAOBJECTIVE: A Canadian multicentre clinical trial in the treatment of intra-abdominal and pelvic infections to compare the efficacy and safety of monotherapy using imipen em-cllastatin (imipenem) (500 mg intravenously every 6 h) versus combination therapy with clindamycin/ tobramycin (clindamycin 600 mg intravenously every 6 h and tobramycin l. 7 mg/kg intraven ously every 8 h). METHoDs: Two hundred and fifty patients were entered (88 definite and 162 possible infections) and all were evalu able for analysis of adverse events and intention to treat analysis of efficacy. Dichotomous outcomes u sed were: cured versus noncured (improved, failed, relapsed). REsULTS: No statistically significant differen ces were found with the intention to treat analysis (P=0.88) or with definite infections (P=0.81). For overall bacteriological response, no significant differen ces were noted (P=0.1). Eleven and 15 patients on imipenem and clindamycin/ tobramycin, respectively, were colonized with bacteria. Enterococci colonized four of 11 imipenem cases and five of 15 clindamycin/ tobramycin cases while fungi colonized six patients on imipenem and four on clindamycin/tobramycin. Five patients on imipenem and seven on clindamycin/tobramycin developed superinfection. In the imipenem group. one case had a bacterial superinfection while four cases were du e to Candida albicans. Seven of seven superinfections on clindamycin/tobramycin were bacterial. Three bacteria initially sen sitive to the assigned study drug developed resistance. In two patients on imipenem, Enterococcus faeca lis and Pseudomonas aeruginosa became resistant after 14 and 10 days of therapy, respectively. On clindamycin/tobramycin, one instance of Bacteroidesjragilis resistance after eight days of therapy was seen. Eigh ty-three adverse events occurred; 4 7 in the imipen em group and 36 in the clindamycin/tobramycin group. This resulted in discontinuation of antibacterial therapy in 13 patients, seven of wh om were on imipenem and six on clindamycin/tobramycin. Comparison of adverse effects showed statistically significant differences for nausea (P=0.02) and hepatotoxicity (P=0.05) occurring with greater frequ en cy in the imipenem and clindamycin/ tobramycin groups, respectively. CoNCLUSIONS: These data support the conclusion that monotherapy with imipenem (500 mg intravenou sly every 6 h) is as efficacious as clindamycin/tobramycin for treatment of intra-abdominal and pelvic infections. Both regimens are well tolerated. (Pour resume, voir page 280)