Hyperosmotic laxatives

Hyperosmotic laxative PO 30-150 ml as a 70% solution Rectal 120mlasa25%-30% solution... 

Hyperosmotic Laxatives. Administration of osmo-tically active substances produces a gradient that draws water into the bowel and small intestine. This gradient increases stool fluid content and stimulates peristalsis. A variety of hyperosmotic substances—including magnesium salts, sodium salts, potassium salts, lactulose, polyethylene glycol, and glycerin—can be used to achieve this effect. 

Lactulose is a hyperosmotic agent, which produces increased osmotic pressure within colon and acidifies its contents, resulting in increased stool water content and stool softening. It causes migration of ammonia from blood into colon, where it is converted to ammonium ion and expelled through laxative action. It is indicated in the treatment of constipation and prevention and treatment of portal-systemic encephalopathy, including stages of hepatic precoma and coma. 

For rectal administration, the osmotic value may vary within wide limits. An osmotic value corresponding to a 0-1.8 % sodium chloride solution is tolerated. Adjusting the iso-osmotic value of an enema, by addition of, for example, sodium chloride, offers no advantage regarding activity and irritation, and can be omitted. StrrMig hyperosmotic solutions must be avoided in enemas, except for those intended as laxative. A strrMigly hyperosmotic solution, for example a phosphate enema, induces a defecation reflex. The osmotic value of this enema is about seven times higher than that of a normal saline solution. 

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