Osmotic cathartics

Both dietary and endogenous ammoniagenic substrates are removed from the intestinal lumen by the osmotic cathartic action of nonabsorbable disaccharides such as lactulose and lactitol. These compounds are currently the main therapeutic agents for chronic HE. The efficacy of oral lactulose for the treatment of HE has been established in controlled trials [41-43]. Besides having a cathartic effect, lactulose lowers the colonic pH as a result of the production of organic acids by bacterial fermentation. The decrease in pH creates an environment that is hostile to the survival of urease-producing intestinal bac-... 

Mechanism of Action A polyalcoholic sugar with osmotic cathartic actions. Specific mechanism unknown. Therapeutic Effect Catharsis, urinary irrigation. Pharmacokinetics Onset of action within 15-60 minutes. Poorly absorbed by both oral and rectal route. Metabolized in liver to primary metabolite, fructose. 

Osmotic cathartics are hypertonic solutions that are absorbed poorly from the lumen of the intestine and draw water into the intestine by passive diffusion. The small intestine has a relatively low density of intercellular tight junctions and consequently should be most responsive to these osmotic agents. The large intestine, a target for osmotic cathartics and a frequent site of impactions of digesta, has a relatively high density of intercellular tight junctions and here the osmotic cathartics should be expected to have less effect. 

There are two types of osmotic cathartics saccharide cathartics (sorbitol) and saline cathartics (magnesium citrate, magnesium sulfate, sodium sulfate). Many charcoal formulations come premixed with sorbitol, but there is considerable variation in the sorbitol content. Multiple doses of cathartics should be avoided. The administration of sorbitol has been associated with vomiting, abdominal cramps, nausea, diaphoresis, and transient hypotension. Multiple doses of sorbitol have been associated with volume depletion. Multiple doses of magnesium-containing cathartics have been associated with severe hypermagnesemia. Children are particularly susceptible to the adverse affects of cathartics, and therefore cathartics should be used with caution, or totally avoided, in children. 

The answer is 5 /If B 3 c (2)J. Sorbitol acts as an osmotic cathartic by attracting water to the intestinal lumen. Overuse may result in excessive Intestinal fluids and diarrhea. The use of sorbitol speeds the passage of gastroirv testinal contents and toxicarTts adsorbed to charcoal, thus removing them from the intestine rapidly and helping to prevent the constipation that may be caused by oral charcoal. 

Osmotic cathartics increase fluid accumulation, stretching the intestinal wall and Initiating reflex propulsive motility. 

Detoxification. Early gastrointestinal detoxification using cme aclivaled charctral, and osmotic cathartics markedly improves the survival tate-... 

Detoxification, Prompt oral decontamination should be performed within 4 hours of acute exposure, using emesis, gastric lavage, activated charcoal, and osmotic cathartics. 

Prompt gastrointestinal drtrmHkalion using activated charcoal and osmotic cathartics is necessary. 

Following gastrointestinal detoxification and the administration of activated charcoal and osmotic cathartics, fluid diuresis should be instituted for 24 hours. 

---