Opioids are typically prescribed in conjunction with either methylnaltrexone bromide or one of these drugs to prevent development of a condition called OIC. Usage of a class of these drugs derived from anthraquinone may cause a black staining of the lamina propria called melanosis coli. The indicator phenolphthalein was historically used as one of these drugs, (15[1])but has been phased out due to carcinogenicity. An isomer of lactose named (*) lactulose functions as one of these drugs by acting as a hyperosmotic agent. Patients are given a large amount of fluids and one of these drugs, typically magnesium citrate or sodium picosulfate, in preparation for a colonoscopy. For 10 points, name these drugs that increase bowel movements or soften stool, and are therefore used to treat constipation. ■END■