INDICATION. PLENVU ® (polyethylene glycol 3350, sodium ascorbate, sodium sulfate, ascorbic acid, sodium chloride, and potassium chloride . for oral solution) is a prescription medication used by adults to clean the colon before a colonoscopy.. IMPORTANT SAFETY INFORMATION. Do not take PLENVU® if you have a blockage in your intestine (bowel obstruction), an opening in the wall of your stomach ....