TABLE 40.1 Classification and Comparison of Representative Laxatives: Type, Cathartic Effect, and Latency

Softening of Formed Stool (1-3 d)

Soft, Semifluid Stool (6-12 hr)

Watery Stool (2-6 hr)

Bulk-forming agents Dietary fiber Methylcellulose Psyllium

Calcium polycarbophil Docusate salts

Sodium, potassium, or calcium salts of dioctyl sulfosuccinate Lactulose Sorbitol

Polyethylene glycol

Saline laxatives (low dose) Milk of magnesia Magnesium sulfate Diphenylmethane derivatives Phenolphthalein Bisacodyl Anthraquinone derivatives Senna

Cascara sagrada

Saline laxatives (high dose) Magnesium citrate Magnesium sulfate Sodium phosphates Castor oil

Polyethylene glycol-electrolyte preparations

Adapted with permission from AMA Drug Evaluations (6th Ed.). Chicago: American Medical Association, 1986.

in increased water content in the feces, the patient should be advised to drink adequate amounts of water; otherwise dehydration may result.

The use of high-fiber diets has recently received a great deal of publicity, and many claims have been made for the value of such diets. Fiber in the diet is derived entirely from plant material, either from fruit and vegetables or from cereals, the latter being known as bran. The fiber content in each case is a complex carbohydrate in the form of cellulose, pectin, and lignin. These fibers pass through the human GI tract relatively unaltered by enzymes.

A high-fiber diet is effective in the prevention of constipation and diverticulitis. Claims also have been made that such diets prevent cancer of the colon. Such allegations require further study.

Since clear advantages accrue from a high-bran diet (a reduction in both constipation and diverticulitis) and since there is no associated toxicity, a bulk-forming laxative is the laxative of choice for constipated patients.

Keep Your Weight In Check During The Holidays

Keep Your Weight In Check During The Holidays

A time for giving and receiving, getting closer with the ones we love and marking the end of another year and all the eating also. We eat because the food is yummy and plentiful but we don't usually count calories at this time of year. This book will help you do just this.

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