Laxatives faecal softeners

Constipation bulk-forming laxatives by increasing faecal mass tend to soften stools and relieve constipation, and have value in a range of symptomatic problems associated with anal fissure, haemorrhoids, and with ileostomy and colostomy dysfunction. Faecal softeners, lactulose and macrogols (polyethylene glycol) retain fluid in the bowel. Stimulant laxatives, such as the anthraquinone, senna, and bisacodyl, increase motility and can cause colic verdoses can cause diarrhea and electrolyte depletion. Chronic treatment for constipation is seldom needed, but may be in children with a tendency to faecal impaction, specialist advice should be sought. 

Drug treatment involves the use of laxatives. There are four main types bulk-forming preparations, hyperosmolar or saline solutions, faecal soften-ers/wetting agents and stimulant or irritant laxatives. 

Faecal softeners act as detergents on the surface of faeces causing them to absorb water and soften. An example is docusate, which can be used prior to imaging. However, other types of laxatives (see below) are better for this purpose. 

These laxatives act by softening and increasing faecal mass thus promoting normal peristalsis. The outer layers of cereal grains, especially wheat, form an important source of natural fibre in the diet and by increasing faecal mass natural fibre has laxative effects. 

Docusate sodium is an anionic surfactant that lowers the surface tension of the intestinal contents, allowing fluid and fat to penetrate, emulsify and soften faecal material for easier elimination. Evacuation is achieved without straining. It is also thought to be a stimulant similar to the anthraquinones. A laxative effect usually occurs within 1-3 days. 

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