Clinical trial: an efficacy evaluation of reduced bisacodyl given as part of a polyethylene glycol electrolyte solution preparation prior to colonoscopy

BACKGROUND: In an attempt to further improve patient preparation experience with reduced volume gut lavage solutions using 2-L sulphate-free electrolyte lavage solution plus 20-mg bisacodyl (HalfLytely with Bisacodyl Tablets Bowel Prep Kit, Braintree Laboratories, Inc., Braintree, MA, USA), a low bisacodyl dose preparation was developed using 10 mg bisacodyl. AIM: To compare preparation methods using the 10- or 20-mg bisacodyl with 2-L sulphate-free electrolyte lavage method. METHODS: At 10 US centres, 455 patients undergoing colonoscopy for routine clinical indications were equally randomized to receive 10- or 20-mg bisacodyl with 2-L sulphate-free electrolyte lavage method. Colonoscopists rated the efficacy of colon cleansing, blinded to the preparation assignment. RESULTS: Physician assessment of colon cleansing showed no difference between those randomized to receive the 10- or 20-mg bisacodyl preparations (P = 0.52). The 10-mg preparation had lower symptom scores for cramping (P < 0.001) and overall discomfort (P = 0.001). Other reported adverse experiences were few, mild and not different between groups. CONCLUSION: Two-litre sulphate-free electrolyte lavage method solution with 10-mg bisacodyl is as effective as the 20-mg bisacodyl preparation for cleansing the colon prior to colonoscopy. The 10-mg bisacodyl regimen has an improved safety profile, with significantly reduced cramping, nausea and overall discomfort.