Table 4.

Pharmacological treatment options for constipation

Types	Agents	Mechanisms of action and effects	Common side effects
Commonly used laxatives
Bulk-forming laxatives	Psyllium, methylcellulose, polycarbophil	Increase water-absorbing properties of stool and decrease stool consistency	Bloating, flatulence
Osmotic laxatives	Sodium phosphate, polyethylene glycol, sorbitol, lactulose, magnesium hydroxide, magnesium citrate, magnesium sulfate	Osmotically increase intraluminal fluids by nonabsorbable ions and molecules and decrease stool consistency	Bloating, flatulence, abdominal cramps, electrolyte disturbance
Stimulants	Diphenylmethane derivatives (bisacodyl, sodium picosulfate), anthraquinones (sennoside, aloe, cascara)	Stimulate mucosa or myenteric plexus to trigger peristaltic contractions and inhibit absorption of water and electrolytes	Abdominal discomfort, pain, and cramps, nausea, incontinence
Stool softeners	Docusate sodium, docusate calcium	Enhance interaction of stool and water	Abdominal cramps, diarrhea
Lubricants	Mineral oil	Lubricate stool and ease passage	Lipid pneumonia, malabsorption of fat-soluble vitamins, incontinence
Newer agents
Chloride channel activators	Lubiprostone	Selectively activate enterocyte type 2 chloride channels (CCl2), resulting in chloride secretion into intestinal lumen followed by passive diffusion of sodium and water	Diarrhea, nausea
Guanylate cyclase C receptor agonists	Linaclotide, plecanatide	Stimulate intestinal epithelial cell guanylate cyclase C receptors, resulting in secretion of chloride, bicarbonate, and water into intestinal lumen and acceleration of stool transit	Diarrhea, nausea
Selective serotonin 5-HT4 receptor agonists	Prucalopride, cisapride, tegaserod	Stimulate intestinal fluid secretion and motility through activation of 5-HT4 receptors of myenteric plexus	Diarrhea, nausea, headache
Ileal bile acid transporters inhibitors	Elobixibat	Reduce ileal reabsorption of bile acids and enhance colonic secretion and motility	Abdominal cramps, diarrhea