These drugs in large or frequent doses may upset the fluid and electrolyte balance in patients without underlying disease. They act by irritating the intestinal mucosa or by directly stimulating the submucosal and myenteric plexus. Some are absorbed, metabolized by the liver, and returned to the bowel in bile. Peristalsis and intraluminal fluid both increase, with cramping and passage of semisolid stool in 6 to 8 h. If these fail, manual fragmentation and disimpaction of the mass are necessary.
Some patients require general anesthesia.
Explanation is important, but it is of little benefit to try to convince an obsessive-compulsive patient that his attitude toward defecation is abnormal, although psychotherapy may help inculcate more rational ideas. Diminished colonic peristalsis or rectal insensitivity to fecal masses. Etiology Colonic inertia occurs in elderly or invalid patients, especially if bedridden. The colon does not respond to the usual stimuli that promote evacuation, or accessory stimuli normally provided by eating and physical activity are lacking. Inertia sometimes occurs in patients whose rectal sensitivity to fecal masses is dulled by habitual disregard of the urge to defecate or by prolonged dependence on laxatives or enemas, often initiated in childhood.