Irritant laxatives

Irritant or stimulant laxatives increase peristalsis by direct action on the intestine. An example of an irritant laxative is cascara sagrada and senna (Senokot). 

A. Small-bowel irritant laxative ricinoleic acid... 

B. Large-bowel irritant laxatives diphenylmethane derivatives... 

N.A. Malva mtundifolia L. M. sylvestris L. Flavonol glycosides, gossypin-3-sulfate, mucilage, tannins, anthocyanin, malvin." A demulcent, a poultice to reduce swelling and draw out toxins. Internally to reduce gut irritation, laxative effect. 

Rectal Alternative to oral route local effect on rectal tissues Poor or incomplete absorption chance of rectal irritation Laxatives suppository forms of other drugs... 

Q7 Laxatives are often misused/abused, for example in slimming disorders, to increase gut transit rate and so limit absorption of foods. Side effects which may occur include flatulence, and abdominal distension or discomfort with bulk-forming and osmotic laxatives. Other adverse effects may include diarrhoea, nausea, vomiting, weakness, dehydration and electrolyte imbalances, for example hypokalaemia. The most prominent side effect of the powerful stimulant/irritant laxatives is abdominal cramping, which is due to increased peristalsis. 

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. 

Irritant laxatives, which cause an increase in secretions through irritation of the intestinal epithelium, and stool softeners, which lubricate the stool or incorporate compliant material into the stool. 

Diarrhea is a common problem that is usually self-limiting and of short duration. Increased accumulations of small intestinal and colonic contents are known to be responsible for producing diarrhea. The former may be caused by increased intestinal secretion which may be enterotoxin-induced, eg, cholera and E. col] or hormone and dmg-induced, eg, caffeine, prostaglandins, and laxatives decreased intestinal absorption because of decreased mucosal surface area, mucosal disease, eg, tropical spme, or osmotic deficiency, eg, disaccharidase or lactase deficiency and rapid transit of contents. An increased accumulation of colonic content may be linked to increased colonic secretion owing to hydroxy fatty acid or bile acids, and exudation, eg, inflammatory bowel disease or amebiasis decreased colonic absorption caused by decreased surface area, mucosal disease, and osmotic factors and rapid transit, eg, irritable bowel syndrome. 

A laxative is most often prescribed for the short-term relief or prevention of constipation. Certain stimulant, emollient, and saline laxatives are used to evacuate the colon for rectal and bowel examinations. Fecal softeners or mineral oil are used prophylactically in patients who should not strain during defecation, such as after anorectal surgery or a myocardial infarction. Psyllium may be used in patients with irritable bowel syndrome and diverticular disease. Fblycarbophil may be prescribed for constipation or diarrhea associated with irritable bowel syndrome and diverticulosis. Mineral oil is... 

Noninfectious causes of acute diarrhea include drugs and toxins (Table 18-3), laxative abuse, food intolerance, irritable bowel syndrome (IBS), inflammatory bowel disease, ischemic bowel disease, lactase deficiency, Whipple s disease, pernicious anemia, diabetes mellitus, malabsorption, fecal impaction, diverticulosis, and celiac sprue. 

Phenolphthalein, like anthraquinones and other irritant phenolic compounds, is a stimulant laxative Colonic peristalsis is increased by stimulation of sensory nerve endings in the mucosa of the intestine. Phenolphthalein also enhances entrance of water and salts into the bowel... 

Glycerin is considered a safe laxative, although it may occasionally cause rectal irritation. Its use is acceptable on an intermittent basis for constipation, particularly in children. 

There can be no objection to the ingestion of bulk substances for the purpose of supplementing low-residue modern diets. However, use of irritant purgatives or cathartics is not without hazards. Specifically, there is a risk of laxative dependence, i.e the inability to do without them. Chronic intake of irritant purgatives disrupts the water and electrolyte balance of the body and can thus cause symptoms of illness (e.g., cardiac arrhythmias secondary to hypokalemia). 

Diphenolmethane derivatives (p. 177) were developed from phenolphthalein, an accidentally discovered laxative, use of which had been noted to result in rare but severe allergic reactions. Bisac-odyl and sodium picosulfate are converted by gut bacteria into the active colon-irritant principle. Given by the enteral route, bisacodyl is subject to hydrolysis of acetyl residues, absorption, conjugation in liver to glucuronic acid (or also to sulfate, p. 38), and biliary secretion into the duodenum. Oral administration is followed after approx. 6 to 8 h by discharge of soft formed stooL When given by suppository, bisacodyl produces its effect within 1 h. 

Laxative effect. Seed hull, taken orally by adults at a dose of 7 g/person, increased weekly fecal mass without influencing transit time or frequency . Seedcoat, administered orally to 80 patients at a dose of 6.4 g/person three times daily, was active in a blinded placebo controlled study of efficacy of extract in treatment of irritable bowel syndrome " . Water extract of the dried kernel, administered orally to 40-year-old adults of both sexes, was active . Seed powder, administered orally to adults of both sexes, was active. Biological activity reported has been patented ". Dried seeds, administered orally to adults at a dose of 0.5 g/person, were active. Placing the seeds in water increased their volume, 90% alcohol produced a decrease in volume to normal seed size, and linseed oil had no effect on volume. The seed mucilage remained in gel form and is considered preferable to the solid form because it is more easily digested " . Dried seed powder, administered orally to 35 patients with chronic constipation at a dose of 50 mg/person, was active in a controlled, double-blind study " . Fiber, administered orally to adults, was active. Psyllium fiber and sennosides were prepared into a wafer to be... 

Stimulant laxatives Bisacodyl, 5-15 mg daily. Senna, dosage varies, consult product labeling Correctol, Dulcolax, Ex-Lax, Senokot, various generic Stimulant laxative actions include direct irritation of intestinal mucosa or stimulation of the myenteric plexus, resulting in peristalsis. These agents may also cause alteration of fluid and electrolyte absorption, resulting in luminal fluid accumulation and bowel evacuation. 

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