A randomized clinical study comparing reduced-volume oral sulfate solution with standard 4-liter sulfate-free electrolyte lavage solution as preparation for colonoscopy

Background: Low-volume bowel preparations for colonoscopy improve tolerability.

Objective: We compared the efficacy, tolerability, and safety of a new low-volume sulfate solution with a standard 4-L polyethylene glycol electrolyte lavage solution as bowel preparation for colonoscopy.

Design: Multicenter, single-blind, randomized, noninferiority study.

Setting: Five academic and community endoscopy centers in the United States.

Patients: One hundred thirty-six outpatients undergoing colonoscopy.

Interventions: Patients were randomized to receive 4 L sulfate-free electrolyte lavage solution (SF-ELS) given the night before colonoscopy versus 12 oz oral sulfate solution (OSS) given in equally divided doses the evening before and the morning of colonoscopy.

Main outcome measurements: Successful (ie, good or excellent) bowel preparation.

Results: Successful bowel preparation was more frequent with OSS than with SF-ELS (98.4% vs 89.6%; P = .04). Excellent preparation also was achieved more frequently with OSS (71.4% vs 34.3%; P < .001). Patients receiving OSS had less residual stool in the cecum and ascending colon and less residual fluid in the cecum and ascending, transverse, and descending colon compared with SF-ELS. The percentage of patients with GI side effects and adverse events was not significantly different between the 2 groups.

Limitations: The OSS was administered in split doses, whereas the SF-ELS was administered the evening before (which is its FDA-approved regimen).

Conclusions: Oral sulfate solution is promising as a safe low-volume preparation for colonoscopy. (

Clinical trial registration number: NCT00856843.).