Laxatives: An update on mechanism of action

Laxatives, traditionally thought to act by stimulating intestinal motility, have other actions which result in laxation. They produce myoelectric alterations in intestinal smooth muscle and induce accumulation of luid in the intestinal lumen; these effects cause rapid transit of material through the bowel. Laxative-induced fluid accumulation may be brought about by inhibition of ion and water absorption, stimulation of fluid secretion, or both concomptantly. Inhibition of cellular energy production or utilization, mucosal injury and activation of adenylate cyclase may be involved in the mucosal action of these agents. The pharmacologic activity of laxatives involves both mucosal and muscle sites of action.