Which mechanism of action is associated with stimulant laxatives?

Stimulant laxatives work primarily by irritating the lining of the gastrointestinal tract. This irritation leads to increased peristalsis, which is the contraction of the muscles in the intestines that propels contents through the digestive system. By stimulating the colon in this manner, stimulant laxatives encourage bowel movements and help alleviate constipation.

The other options describe mechanisms associated with different types of laxatives. For instance, drawing water into the colon is characteristic of osmotic laxatives, which retain water in the intestines to soften stool and stimulate bowel movements. Inhibiting sodium reabsorption is more relevant to certain electrolyte-based treatments rather than to stimulant laxatives specifically. Lastly, creating a softer stool is a function of stool softeners, which typically add moisture to the stool rather than stimulating the bowel directly. Each of these mechanisms serves a different purpose in the treatment of constipation, highlighting how stimulant laxatives uniquely enact their effects through direct stimulation and irritation.