Miralax (PEG 3350) vs. Golytely as Bowel Preparation for Screening Colonoscopy

Study Summary

A major limitation to the widespread acceptance of colonoscopy as a procedure to screen for colorectal cancer is the laxative preparation. Phosphate-based preps (e.g. Fleets Phosphosoda) are now used on a limited basis because of their known association with renal injury. Polyethylene glycol (PEG) mixed with a balanced electrolyte solution (e.g. Golytely) has been used for over two decades for colon cleansing. The mixture is not very palatable due to the electrolyte additives which include sodium sulfate. To overcome the limitation of existing preps, gastroenterologists and colorectal surgeons worldwide have been using PEG powder alone (same quantity as found in Golytely prep) not mixed with electrolytes (Glycolax or Miralax) and dissolving this into 64 ounces of Gatorade. Conservatively, we estimate that 25% of colonoscopies in the US are being done with this prep. Anecdotally there have been reports (case series) that it is far more palatable and the prep is equally efficacious. The active ingredient, PEG, is not changed and therefore this is not surprising. The issue at present is that there has never been a blinded study to confirm these claims. This study will compare the efficacy of the two preps. There is no funding. The investigators will charge insurance companies for the prep - this is our current practice. The procedures will be done on healthy individuals referred for colon cancer screening and the exam will be billed to their insurance. There will be no patient honorarium. The investigators will check electrolytes to be sure patients do not develop hypokalemia with the Gatorade prep.

Primary Outcome

The study is a non-inferiority study: The objective is to conclude that the prep quality scores of those receiving Miralax is at most 10% less than for Golytely. Thus the difference in prep scores between Miralax minus Golytely should be greater than - 10%. If this is the case, Miralax would be considered as non-inferior to Golytely. The outcome measure will use the Boston Prep Scale. The BPS is scored 0-9 with 9 being an excellent preparation throughout the colon. From the right colon, transve

Interventions

• DRUG PEG-3350 and Gatorade
• DRUG Golytely 4 liters