Imipenem versus netilmicin and vancomycin in the treatment of CAPD peritonitis

Imipenem/cilastatin is a new thienamycin antibiotic with a broad bactericidal spectrum. We undertook a prospective randomised study to compare the safety and efficacy of intraperitoneal (IP) imipenem/cilastatin (2 gm daily) [group A; 21 patients, mean age 49.2 years] with a combination of IP netilmicin and vancomycin (500 and 60-100 mg daily resp.) [group B; 20 patients, mean age 55.2 years] in CAPD peritonitis. Each patient underwent 4 daily CAPD exchanges with antibiotics in alternate exchanges. The causative organisms were similar in both the groups as was the duration of therapy (gr.A: 6.8 +/- 0.27 days; gr.B: 7.2 +/- 0.51 days; p = NS). Complete cure was marginally better with imipenem/cilastatin (gr.A; 94.1%, gr.B: 83.3%) with less relapses (gr.A: 1 episode; gr.B: 3 episodes). One episode in gr.A (S. aureus) and 2 in gr.B (Yeast & Proteus) failed to resolve and required catheter removal. Two gr. A patients developed generalised convulsions which settled after discontinuation of the drug. Whilst the results show no significant difference in the outcome in the two groups, the use of IP imipenem would offer a possible advantage as a single antibiotic. Larger experience is needed before imipenem can be recommended as a 'blind' first line agent for CAPD peritonitis.