Osmotic laxative
- Osmotically retains water in the bowel lumen
- Softer stool and laxation without stimulating the mucosa
- The gentlest laxative class
Drugs with this mechanism (4)
- Lactulose — Non-absorbed disaccharide; osmotic laxative that also traps ammonia in the colon.
- Mg hydroxide — OTC osmotic laxative and antacid (milk of magnesia).
- PEG 3350/ electrolytes — PEG-electrolyte bowel preparation; effective with little net fluid or electrolyte shift.
- PEG 3350 — Well-tolerated OTC osmotic laxative for chronic constipation and bowel preparation.
Self-check
- Where do osmotic GI agents retain water?
In the bowel lumen. - Must osmotic laxatives stimulate the mucosa to soften stool?
No.
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