Background and purpose: Intra-abdominal infections are a substantial clinical problem and an important cause of morbidity and death in the hospital. Optimal treatment requires both source control and antibiotic therapy. Sequential intravenous (IV) to oral therapy may improve patient convenience and reduce total health care costs. In this randomized, double-blind trial, the efficacy of sequential IV-to-oral ciprofloxacin plus metronidazole was compared with ceftriaxone plus metronidazole in adult patients with complicated intra-abdominal infections.
Methods: The trial enrolled 531 patients, who began with IV therapy. Patients who improved clinically were switched to oral therapy on day three or later. The clinical and bacteriological responses four to six weeks after the end of therapy and the safety of the two regimens were assessed. To maintain blinding, the patients received placebo IV in the ciprofloxacin group or placebo orally in the ceftriaxone group. A total of 475 patients (235 ciprofloxacin plus metronidazole, 240 ceftriaxone plus metronidazole) were valid for evaluation of efficacy. All patients were included in the safety analysis.
Results: Of the patients valid for efficacy, 78% of the ciprofloxacin plus metronidazole group and 81% of the ceftriaxone plus metronidazole group were eligible for a switch to oral therapy. The clinical success rates were 98.9% and 96.9%, respectively, which were statistically equivalent. The clinical success rates for all patients, including those on continuous IV therapy, were 90.6% and 87.9%. Source control was achieved in more than 90% of the patients. The bacteriological eradication rates were similar in the two groups. Bacterial complications (e.g., surgical site infections, abscesses) were encountered more often in the ceftriaxone plus metronidazole group.
Conclusions: Sequential ciprofloxacin plus metronidazole IV-to-oral therapy was statistically equivalent to ceftriaxone plus metronidazole. The switch to oral therapy with ciprofloxacin plus metronidazole was as effective and safe as continued IV therapy in patients able to tolerate enteral feeding.