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.
