Amitiza® Plus GoLYTELY® (PEG) Versus Placebo Plus GoLYTELY® for Outpatient Colonoscopy Preparation

The primary objective is to compare the effectiveness and tolerance of the medication named lubiprostone plus a large volume liquid laxative versus placebo which is a look alike medication that has no effect such as a sugar pill plus a large volume liquid laxative as a bowel cleaning preparation for colonoscopy to see the colon better during the colonoscopy to identify abnormal growths such as polyps or colon cancer. Colonoscopy is considered the best way to screen for colon cancer screening because you can visualize the colon directly and remove or biopsy abnormal growths. The limiting step in the procedure is the quality of the colon preparation prior to the procedure. Many patients do not tolerate large volumes of liquid used to prepare the colon. The purpose of the study is to improve the quality of the prep by adding a pill laxative medication before starting the large volume laxative to better see the colon. The other aim of the study is to try to reduce the amount of of liquid laxative the patient has to drink by giving a pill laxative before starting the liquid laxative.