22.7 : 影响胃肠道蠕动的药物：其他泻药

Recall that laxatives facilitate coordinated gut movement or change stool's consistency to relieve constipation.

Stool softeners, such as docusate sodium, are surfactants that enable the blending of aqueous and lipid contents, easing the process of defecation.

Lubricant laxatives, such as mineral oil, create a slippery coat by penetrating the stool, expediting its passage through the intestines. It is administered orally upright to prevent lipid pneumonia due to accidental aspiration.

Next, osmotic laxatives are nonabsorbable agents that retain water, enhancing stool liquidity and promoting its movement through the colon. For example, magnesium hydroxide and lactulose are effective for chronic constipation but can lead to flatulence, diarrhea, and abdominal cramps if overused.

Lastly, lavage solutions consist of balanced PEG solutions—a mixture of polyethylene glycol, an osmotically active sugar, and electrolytes. They are primarily employed to cleanse the colon before procedures such as colonoscopies, gastric surgeries, or endoscopies.