Treatment of chronic constipation: current pharmacologic approaches and future directions.

Chronic constipation is a common condition that affects up to 27% of the population. Dietary and lifestyle measures are usually the first-line therapy, but if these fail to have an effect then a variety of prescription and consumer laxatives are available. Traditional laxatives include bulking agents, osmotic agents, stool softeners, and stimulants of the gastrointestinal tract. All have been found to be more effective than placebo at relieving symptoms of constipation, but these results have been obtained primarily in short (4-week) trials and no class of laxative has been shown to be superior to another. Traditional laxatives work in many, but not all, patients and some patients cannot cope with the side effects, unpleasant taste, the requirements of the dosing regimen, or the notion of dose increase. New enterokinetic agents that affect peristalsis through selective interaction with 5-hydroxytryptamine-4 receptors and novel agents acting on intestinal secretion could offer an alternative option for patients with chronic constipation who cannot get adequate relief from current laxatives.