The Effect of Adding Lubiprostone to Standard Large-Volume PEG-ELS on The Quality of Inpatient Colonoscopy Preparation

Inclusion Criteria: * Is scheduled for colonoscopy evaluation during his hospitalization to one of the trial sites (SJPH, PPH, or SJMH). * Has a negative urine pregnancy test (hCG) for female of reproductive age. * Provide an Informed Consent / has a legally acceptable representative capable of understanding the Informed Consent document and providing consent on the participant's behalf. * Provide a separate signed and dated Informed Consents for colonoscopy procedure and anaesthesia administration as per site policy. Exclusion Criteria: * Has a documented or suspected bowel obstruction (small bowel obstruction, volvulus, gastric outlet obstruction, ileus, or toxic megacolon). * Has a documented gastroparesis. * Has severe diarrhea (\>8 bowel movements per day). * Has severe encephalopathy or obtunded (GCS \< 13). * Has a documented or suspected acute coronary syndrome or recent myocardial infarction within 12 weeks prior to enrollment. * Has renal impairment with GFR less than 30 ml/min/1.73 m2 on the day of enrollment (end-stage renal disease on renal replacement therapy can be enrolled). * Has severe liver impairment with Child-Pugh class B or C. * Has symptomatic heart failure (NYHA class III or IV) or prohibitive pre-procedure cardiac risk (documented by primary team or cardiology prior to enrollment). * Has a known hypersensitivity to Lubiprostone or its class. * Is pregnant or lactating.