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laxative

 

Definition

Laxatives are products that promote bowel movements.

Description

Laxatives may be grouped by mechanism of action.

Saline cathartics include dibasic sodium phosphate (Phospo-Soda), magnesium citrate, magnesium hydroxide (milk of magnesia), magnesium sulfate (Epsom salts), sodium biphosphate, and others. They act by attracting and holding water in the intestinal lumen, and may produce a watery stool. Magnesium sulfate is the most potent of the laxatives in this group.

Stimulant and irritant laxatives increase the peristaltic movement of the intestine. Examples include cascara and bisadocyl (Dulcolax.) Castor oil works in a similar fashion.

Bulk producing laxatives increase the volume of the stool, and will both soften the stool and stimulate intestinal motility. Psyillium (Metamucil, Konsil) and methylcellulose (Citrucel) are examples of this type. The overall effect is similar to that of eating high-fiber foods, and this class of laxative is most suitable for regular use.

Docusate (Colace) is the only representative example of the stool softener class. It holds water within the fecal mass, providing a larger, softer stool. Docusate has no effect on acute constipation, since it must be present before the fecal mass forms to have any effect, but may be useful for prevention of constipation in patients with recurrent problems, or those who are about to take a constipating drug, such as narcotic analgesics.

Mineral oil is an emollient laxative. It acts by retarding intestinal absorption of fecal water, thereby softening the stool.

The hyperosmotic laxatives are glycerin and lactulose (Chronulac, Duphalac), both of which act by holding water within the intestine. Lactulose may also increase peristaltic action of the intestine.

— Samuel D. Uretsky, PharmD



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Dictionary: lax·a·tive   (lăk'sə-tĭv) pronunciation
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n.
A food or drug that stimulates evacuation of the bowels.

adj.
  1. Stimulating evacuation of the bowels.
  2. Causing looseness or relaxation, especially of the bowels.

[Middle English, from Old French laxatif, from Medieval Latin laxātīvus, preventing constipation, from Late Latin, assuaging, from Latin laxātus, past participle of laxāre, to relax, from laxus, loose. See lax.]


laxative
Substance that promotes defecation. These include irritants (stimulants) such as cascara sagrada and castor oil, bulk formers such as bran and psyllium, saline laxatives such as Epsom salts or milk of magnesia, glycerin, lubricants such as mineral oil and some vegetable oils, and stool softeners. A high-fibre diet is more important than laxatives in correcting simple intestinal constipation.

For more information on laxative, visit Britannica.com.

Surgery Encyclopedia:

Laxatives

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Definition

Laxatives are products that promote bowel movements.

Purpose

Laxatives are used to treat constipation—the passage of small amounts of hard, dry stools, usually fewer than three times a week. Before recommending use of laxatives, differential diagnosis should be performed. Prolonged constipation may be evidence of a significant problem such as localized peritonitis or diverticulitis. Complaints of constipation may be associated with obsessive-compulsive disorder. Use of laxatives should be avoided in these cases. Patients should be aware that patterns of defecation are highly variable, and may vary from two to three times daily to two to three times weekly.

Laxatives may also be used prophylacticly for patients such as those recovering from a myocardial infarction (heart attack) or those who have had recent surgery and should not strain during defecation.

Description

Laxatives may be grouped by mechanism of action.

Saline cathartics include dibasic sodium phosphate (Phospo-Soda), magnesium citrate, magnesium hydroxide (milk of magnesia), magnesium sulfate (Epsom salts), sodium biphosphate, and others. They act by drawing to and holding water in the intestinal tissues, and may produce a watery stool. Magnesium sulfate is the most potent of the laxatives in this group.

Stimulant and irritant laxatives increase the peristaltic movement of the intestine. Product examples include cascara and bisadocyl (Dulcolax). Castor oil works in a similar fashion.

Bulk-producing laxatives increase the volume of the stool, and will both soften the stool and stimulate intestinal motility. Psyillium (Metamucil, Konsil) and methyl-cellulose (Citrucel) are examples of this type. The over-all effect is similar to that of eating high-fiber foods, and this class of laxative is most suitable for regular use.

Docusate (Colace) is the only representative example of the stool softener class. It holds water within the fecal mass, providing a larger, softer stool. Docusate has no effect on acute constipation, since it must be present before the fecal mass forms to have any effect, but may be useful for prevention of constipation in patients with recurrent problems, or those who are about to take a constipating drug such as narcotic analgesics.

Mineral oil is an emollient laxative. It acts by retarding intestinal absorption of fecal water, thereby softening the stool.

The hyperosmotic laxatives are glycerin and lactulose (Chronulac, Duphalac), both of which act by holding water within the intestine. Lactulose may also increase peristaltic action of the intestine.

Precautions

Short-term use of laxatives is generally safe except in cases of appendicitis, fecal impaction, or intestinal obstruction. Lactulose is composed of two sugar molecules, galactose and fructose, and should not be administered to patients who require a low-galactose diet.

Chronic use of laxatives may result in fluid and electrolyte imbalances, steatorrhea, osteomalacia, diarrhea, cathartic colon, and liver disease. Excessive intake of mineral oil may cause impaired absorption of oil soluble vitamins, particularly A and D. Excessive use of magnesium salts may cause hypermanesemia.

Lactulose and magnesium sulfate are pregnancy category B. Casanthranol, cascara sagrada, danthron, docusate sodium, docusate calcium, docusate potassium, mineral oil, and senna are category C. Casanthranol, cascara sagrada, and danthron are excreted in breast milk, resulting in a potential increased incidence of diarrhea in the nursing infant.

Interactions

Mineral oil and docusate should not be used in combination. Docusate is an emulsifying agent that will increase the absorption of mineral oil.

Bisacodyl tablets are enteric coated, and so should not be used in combination with antacids. The antacids will cause premature rupture of the enteric coating.

Recommended Dosage

The consumer is advised to see specific resources for each product.

Resources

Periodicals

"Constipation, Laxatives and Dietary Fiber." HealthTips (April 1993): 9.

"Overuse Hazardous: Laxatives Rarely Needed." FDA Consumer (April 1991): 33.

Organizations

National Digestive Diseases Information Clearinghouse. 2 Information Way, Bethesda, MD 20892-3570. nddic@aerie.com. http://www.niddk.nih.gov/Brochures/NDDIC.htm.

Other

"Effectiveness of Laxatives in Adults." Centre for Reviews and Dissemination, University of York. [cited June 2003] http://www.york.ac.uk/inst/crd/ehc71.htm.

"Laxatives (Oral)." Medline Plus Drug Information. [cited June 2003] http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202319.html.

— Samuel D. Uretsky, PharmD

Oncology Encyclopedia:

Laxatives

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Key Terms: Cathartic, Constipation, Diarrhea, Electrolyte levels, Encephalopathy, Peristalsis.

Definition

A laxative is a drug that promotes bowel movements.

Purpose

Laxatives are used to prevent or treat constipation. They are also used to prepare the bowel for an examination or surgical procedure.

Description

Laxatives work in different ways, by stimulating colon movement, adding bulk to the contents of the colon, or drawing fluid or fat into the intestine. Some laxatives work by combining these functions. Most primary care physicians recommend that patients try the bulk-producing laxatives first before taking saline or stimulant laxatives.

Bisacodyl

Bisacodyl is a non-prescription stimulant laxative. It reduces short-term constipation and is also used to prepare the colon or rectum for an examination or surgical procedure. The drug works by stimulating colon movement (peristalsis); constipation is usually relieved within 15 minutes to one hour after administration of a suppository form and in 6 to 12 hours after taking the drug orally.

Calcium Polycarbophil

Calcium polycarbophil is a non-prescription bulk-forming laxative that is used to reduce both constipation and diarrhea. It draws water to the intestine, enlarging the size of the colon and thereby stimulating movement. It reduces diarrhea by taking extra water away from the stool. This drug should relieve constipation in 12 to 24 hours and have maximum effect in three days. Colitis patients should see a reduction in diarrhea within one week.

Docusate Calcium/Docusate Sodium

Docusate, a non-prescription laxative, helps a patient avoid constipation by softening the stool. It works by increasing the penetration of fluids into the stool by emulsifying feces, water and fat. Docusate prevents constipation and softens bowel movements and fecal impactions. This laxative should relieve constipation within one to three days.

Lactulose

Lactulose, a prescription laxative, reduces constipation and lowers blood ammonia levels. It works by drawing fluid into the intestine, raising the amount of water in the stool, and preventing the colon from absorbing ammonia. It is used to help people who suffer from chronic constipation.

Psyllium

Psyllium is a non-prescription bulk-forming laxative that reduces both constipation and diarrhea. It mixes with water to form a gel-like mass that can be easily passed through the colon. Constipation is relieved in 12 to 24 hours and maximum relief is achieved after several days.

Senna/Senokot

Senna/senokot is a non-prescription laxative that reduces constipation by promoting colon movement. It is used to treat bouts of constipation and to prepare the colon for an examination or surgical procedure. This laxative reduces constipation in eight to 10 hours.

New and Investigational Treatments for Constipation

Some newer options for the treatment of chronic constipation are being developed by various groups of researchers. These include such alternative therapies as biofeedback; newer drugs like tegaserod (Zelnorm) and prucalopride, which stimulate peristalsis; a nerve growth factor known as neurotrophin-3; and electrical stimulation of the colon.

Recommended Dosage

Laxatives may be taken by mouth or rectally (suppository or enema).

Bisacodyl

  • Adults or children over 12 years: 5 to 15 mg taken by mouth in morning or afternoon (up to 30 mg for surgical or exam preparation).
  • Adult (rectal): 10 mg.
  • Children age 2 to 11 years: 10 mg rectally as single dose.
  • Children over three years: 5 to 10 mg by mouth as single dose.
  • Children under two years: 5 mg rectally as single dose.

Calcium Polycarbophil

  • Adult: 1 g by mouth every day, up to four times a day as needed (not to exceed 6 g by mouth in a 24-hour time period).
  • Children age 6 to 12 years: 500 mg by mouth twice a day as needed (not to exceed 3 g in a 24-hour time period).
  • Children age 3 to 6 years: 500 mg twice a day by mouth, as needed (not to exceed 1.5 g in a 24-hour time period).

Docusate

  • Adult (docusate sodium): 50 to 300 mg by mouth per day.
  • Adult (docusate calcium or docusate potassium): 240 mg by mouth as needed.
  • Adult (docusate sodium enema): 5 ml.
  • Children over 12 years (docusate sodium enema): 2 ml.
  • Children age 6 to 12 years (docusate sodium): 40 to 120 mg by mouth per day.
  • Children age 3 to 6 years (docusate sodium): 20 to 60 mg by mouth per day.
  • Children under 3 years (docusate sodium): 10 to 40 mg by mouth every day.

Lactulose

For Constipation:

  • Adult: 15 to 60 ml by mouth every day.
  • Children: 7.5 ml by mouth every day.

For Encephalopathy:

  • Adult: 20 to 30 g three or four times a day until stools become soft. Retention enema: 30 to 45 ml in 100 ml of fluid.
  • Infants and children: Parents should follow physician's directions for infants and children with encephalopathy.

Psyllium

  • Adult: 1 to 2 teaspoons mixed in 8 ounces of water two or three times a day by mouth, followed by 8 ounces water; or one packet in 8 ounces water two or three times a day, followed by 8 ounces of water.
  • Children over 6 years: 1 teaspoon mixed in 4 ounces of water at bedtime.

Senna/Senokot

  • Adult (Senokot): 1 to 8 tablets taken by mouth per day or 1/2 to 4 teaspoons of granules mixed in water or juice.
  • Adult (rectal suppository): 1 to 2 at bedtime.
  • Adult (syrup): 1 to 4 teaspoons at bedtime.
  • Adult (Black Draught): 3/4 ounce dissolved in 2.5 ounces liquid given between 2 p.m. and 4 p.m. on the day prior to a medical exam or procedure.
  • Children: Parents should ask their doctor as dosage is based on weight. Black Draught is not to be used by children.
  • Children age 1 month to 1 year (Senokot): 1.25 to 2.5 ml of syrup at bedtime.

Precautions

The doctor should be informed of any prior allergic drug reaction, especially prior reactions to any laxatives. Pregnancy is also a concern. Animal studies have shown laxatives to have adverse effects on pregnancy, but no human studies regarding pregnancy are currently available. These drugs are only given in pregnancy after the risks to the fetus have been taken under consideration. Nursing mothers should use caution and consult their doctors before receiving these drugs.

Bisacodyl should not be administered to patients with rectal fissures, abdominal pain, nausea, vomiting, appendicitis, abdominal surgery, ulcerated hemorrhoids, acute hepatitis, fecal impaction, or blockage in the biliary tract. Calcium polycarbophil should not be given to anyone with a gastrointestinal blockage (obstruction).

Both psyllium and docusate calcium/docusate sodium should be avoided by patients with intestinal blockage, fecal impaction, or nausea and vomiting. Lactulose should be avoided by patients who are elderly, have diabetes mellitus, eat a low galactose diet, or whose general health is poor.

Senna/senokot is inadvisable for patients with congestive heart failure, gastrointestinal bleeding, intestinal blockage, abdominal pain, nausea and vomiting, appendicitis, or prior abdominal surgery.

The American College of Toxicology states that cathartics should not be used as a means of clearing poisons from the digestive tract of a poisoning victim. Although some physicians have administered these laxatives along with activated charcoal in order to reduce the body's absorption of the poison, this treatment is no longer recommended.

Side Effects

Laxatives may have side effects. Some, such as nausea and vomiting, are more common than others. Side effects related to specific laxatives are described in this section. With repeated use, people may become dependent on laxatives. All side effects should be reported to a doctor.

Bisacodyl

Common side effects:

  • nausea
  • vomiting
  • loss of appetite (anorexia)
  • cramps

Less common side effects:

  • muscle weakness
  • diarrhea
  • electrolyte changes
  • rectal burning (when suppositories are used).

Life-threatening:

Calcium Polycarbophil

Side effects may include:

  • abdominal bloating (distention)
  • gas
  • laxative dependency

Life-threatening:

  • gastrointestinal obstruction

Docusate Calcium/Docusate Sodium

Side effects include:

  • bitter taste in the mouth
  • irritated throat
  • nausea
  • cramps
  • diarrhea
  • loss of appetite
  • rash

Lactulose

Common side effects include:

  • nausea
  • vomiting
  • loss of appetite
  • abdominal cramping
  • bloating
  • belching
  • diarrhea

Psyllium

Common side effects include:

  • nausea
  • vomiting
  • loss of appetite
  • diarrhea

Less common side effects include:

  • abdominal cramping
  • blockage of the esophagus or intestine

Senna/Senokot

Common side effects include:

  • nausea
  • vomiting
  • loss of appetite
  • abdominal cramping

Less common side effects include:

  • diarrhea
  • gas
  • urine that is pink-red or brown-black in color
  • abnormal electrolyte levels

Life-threatening:

  • Severe muscle spasms (tetany)

Interactions

Laxatives may interact with other drugs. Sometimes, the laxative can interfere with proper absorption of another drug. A patient must notify their doctor or pharmacist if he or she is already taking any medications so that the proper laxative can be selected or prescribed. Specific drug interactions are:

  • Bisacodyl: Antacids, H2-blockers, and some herbal remedies (lily of the valley, pheasant's eye, squill).
  • Calcium polycarbophil: (lowers the absorption of) tetracycline.
  • Docusate calcium/docusate sodium: Unknown.
  • Lactulose: Neomycin and other laxatives.
  • Psyllium: Cardiac glycosides, oral anticoagulants, and salicylates.
  • Senna/senokot: Disulfiram should never be taken with this drug. Also, senna/senokot lowers the absorption of other drugs taken by mouth.

Resources

Books

Beers, Mark H., MD, and Robert Berkow, MD, editors. "Diarrhea and Constipation." Section 3, Chapter 27 in The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Karch, A. M. Lippincott's Nursing Drug Guide. Springhouse, PA: Lippincott Williams & Wilkins, 2003.

Periodicals

DiPalma, J. A. "Current Treatment Options for Chronic Constipation." Reviews in Gastroenterological Disorders 4, Supplement 2 (2004): S34–S42.

Newton, G. D., W. S. Pray, and N. G. Popovich. "New OTC Drugs and Devices 2003: A Selective Review." Journal of the American Pharmaceutical Association 44 (March-April 2004): 211–225.

"Position Paper: Cathartics." Journal of Toxicology: Clinical Toxicology 42 (March 2004): 243–253.

Schiller, L. R. "New and Emerging Treatment Options for Chronic Constipation." Reviews in Gastroenterological Disorders 4, Supplement 2 (2004): S43–S51.

Talley, N. J. "Management of Chronic Constipation." Reviews in Gastroenterological Disorders 4 (Winter 2004): 18–24.

Organizations

American Society of Health-System Pharmacists (ASHP). 7272 Wisconsin Avenue, Bethesda, MD 20814. (301) 657–3000. .

National Digestive Diseases Information Clearinghouse. 2 Information Way, Bethesda, MD 20892-3570. nddic@aerie.com. .

United States Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857-0001. (888) INFO-FDA. .

—Rhonda Cloos, R.N.; Rebecca J. Frey, Ph.D.

Food and Nutrition:

laxative

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Or aperient

a substance that helps the expulsion of food residues from the body. If strongly laxative it is termed purgative or cathartic. Dietary fibre and cellulose function because they retain water and add bulk to the contents of the intestine; Epsom salts (magnesium sulphate) also retain water; castor oil and drugs such as aloes, senna, cascara, and phenolphthalein irritate the intestinal mucosa. Undigested carbohydrates such as lactulose and sugar alcohols are also laxatives.

Food and Fitness:

laxative

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A substance that increases the frequency of bowel movements. It may also be used to encourage the formation of a softer or bulkier stool. Common laxatives include castor oil, senna (and its derivatives), magnesium sulphate, and some bulking agents (e.g. bran and methyl cellulose). Some common laxatives, such as castor oil and senna, irritate the gut lining and can cause severe cramps. They are sometimes used by people trying to lose weight but they can result in dehydration and malabsorption of nutrients, leading to nutrient deficiencies. Most experts agree that taking such laxatives is a dangerous and ineffective way to lose weight.

Definition

Laxatives are products that promote bowel movements.

Description

Laxatives may be grouped by mechanism of action.

Saline cathartics include dibasic sodium phosphate (Phospo-Soda), magnesium citrate, magnesium hydroxide (milk of magnesia), magnesium sulfate (Epsom salts), sodium biphosphate, and others. They act by attracting and holding water in the intestinal lumen, and may produce a watery stool. Magnesium sulfate is the most potent of the laxatives in this group.

Stimulant and irritant laxatives increase the peristaltic movement of the intestine. Examples include cascara and bisadocyl (Dulcolax). Castor oil works in a similar fashion.

Bulk producing laxatives increase the volume of the stool, and will both soften the stool and stimulate intestinal motility. Psyillium (Metamucil, Konsil) and methylcellulose (Citrucel) are examples of this type. The overall effect is similar to that of eating high-fiber foods, and this class of laxative is most suitable for regular use.

Docusate (Colace) is the only representative example of the stool softener class. It holds water within the fecal mass, providing a larger, softer stool. Docusate has no effect on acute constipation, since it must be present before the fecal mass forms to have any effect, but may be useful for prevention of constipation in patients with recurrent problems, or those who are about to take a constipating drug, such as narcotic analgesics.

Mineral oil is an emollient laxative. It acts by retarding intestinal absorption of fecal water, thereby softening the stool.

The hyperosmotic laxatives are glycerin and lactulose (Chronulac, Duphalac), both of which act by holding water within the intestine. Lactulose may also increase peristaltic action of the intestine.

General Use

Laxatives are used to treat constipation—the passage of small amounts of hard, dry stools, usually fewer than three times a week. Constipation may be caused by several conditions, some of which are potentially serious, and require medical attention:

  • Neurologic—caused by failure of nerves to stimulate movement of the muscles of the intestines.
  • Obstructive—failure of the muscles in the intestine to open, or presence of a mass that's blocking passage of the feces through the intestine.
  • Endocrine/metabolic—caused by some diseases including hypothyroidism.
  • Medicinal—caused by some drugs, including narcotic analgesics, iron, and some drugs used in cancer treatment.

Chronic constipation occurs in 1–4% of children between the ages of four and 10. If constipation continues, it should be treated by a physician.

A reasonable first step is to assure that there is enough fiber in the diet. This may be done by switching to a high fiber breakfast cereal. If this doesn't lead to improvement, then medical attention is necessary.

Precautions

Short term use of laxatives is generally safe except in appendicitis, fecal impaction, or intestinal obstruction. Lactulose is composed of two sugar molecules; galactose and fructose, and should not be administered to patients who require a low galactose diet.

Chronic use of laxatives may result in fluid and electrolyte imbalances, steatorrhea, osteomalacia, diarrhea, cathartic colon, and liver disease. Excessive intake of mineral oil may cause impaired absorption of oil soluble vitamins, particularly A and D. Excessive use of magnesium salts may cause hypermanesemia.

Side Effects

Excessive use of laxatives may result in dependency on these products. This may cause a condition known as cathartic colon.

Excessive use of laxatives that contain sodium or magnesium may result in dangerously high blood levels of these elements.

Interactions

Mineral oil and docusate should not be used in combination. Docusate is an emulsifying agent which will increase the absorption of mineral oil.

Bisacodyl tablets are enteric coated, and so should not be used in combination with antacids. The antacids will cause premature rupture of the enteric coating.

Preventing Side Effects

Used properly, laxatives are very safe. Do not overuse or give in doses larger than those labeled. If constipation persists, obtain medical help.

Parental Concerns

Laxatives should not be used too frequently. Bulk laxatives such as psyllium should be the normal first choice.

Mineral oil should not be given to infants or other children while laying down. This may result in the oil going into the lungs.

Resources

Books

Beers, Mark H. and Robert Berkow, eds. The Merck Manual of Diagnosis and Therapy, 17th ed. Whitehouse Station, NJ: Merck and Company, Inc., 1999.

McAvoy, G., Miller J., Litvak K. AHFS Drug Information 2004. Amer. Soc Healthsys. Pharm, Bethesda 2004.

Siberry G.K., Iannone R. The Harriet Lane Handbook 15th ed. Mosby Publishing, Philadelphia, 2000.

Periodicals

Bell, EA, Wall, GC. "Pediatric constipation therapy using guidelines and polyethylene glycol 3350." Ann Pharmacother. 2004 Apr;38(4):686-93.

"Constipation, Laxatives and Dietary Fiber." HealthTips (April 1993): 9.

Griffin, GC, Roberts, SD, Graham, G. "How to resolve stool retention in a child. Underwear soiling is not a behavior problem." Postgrad Med 1999 Jan;105(1):159-61, 165-6, 172-3.

"Overuse Hazardous: Laxatives Rarely Needed." (Includes related article on types of laxatives.) FDA Consumer (April 1991): 33.

Patel, H, Law, A, Gouin, S. "Predictive factors for short-term symptom persistence in children after emergency department evaluation for constipation." Arch Pediatr Adolesc Med. 2000 Dec;154(12):1204-8.

Organizations

American Academy of Family Physicians 11400 Tomahawk Creek Parkway Leawood, KS 66211-2672.

Web Sites

Constipation in Infants and Children: Evaluation and Treatment. American Academy of Pediatrics. (accessed February 15, 2005).

Section on Gastroenterology and Nutrition (SOGN). American Academy of Pediatrics. (accessed February 15, 2005).

[Article by: Samuel Uretsky, PharmD]



 
Columbia Encyclopedia:

laxative

Top
laxative, drug or other substance used to stimulate the action of the intestines in eliminating waste from the body. The term laxative usually refers to a mild-acting substance; substances of increasingly drastic action are known as cathartics, purgatives, hydrogogues, and drastics, respectively. Laxatives or cathartics fall into three general categories: irritants that stimulate the muscular action of the intestines (cascara, phenolphthalein, senna); compounds that increase the amount of bulk in the intestines either by withdrawing water from the body (salines such as Epsom salts, citrate of magnesia) or by increasing the bulk when combined with fluids (agar-agar, bran, the various cellulose substances); and lubricants such as mineral oil, which ease the passage of waste and counteract excessive drying of the intestinal contents. Frequent or regular use of cathartics may seriously disrupt the natural digestive processes. When food and even waste products are forced out of the intestinal tract too rapidly, the body is deprived of vital substances, including the nutrients absorbed in the small intestine and the water, vitamins, and minerals extracted from the waste matter in the large intestine. Vitamins A and D, which are soluble in oil, are removed from the body even when the least irritating laxative, mineral oil, is taken. In addition to disrupting digestive and nutritional processes, laxatives reinforce the condition they are intended to overcome. When the intestines are purged, it may be several days before they can fill again with sufficient waste to induce natural elimination. The harm can be perpetuated by frequent use aimed at forcing daily elimination. The response to laxatives is soon lessened, so that larger and more frequent doses may become necessary. Laxatives should be avoided especially when there is abdominal pain. An inflamed appendix may rupture after the use of a laxative. See constipation.


Veterinary Dictionary:

laxative

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A medicine that loosens the bowel contents and encourages evacuation. A laxative with a mild or gentle effect on the bowels is also known as an aperient; one with a strong effect is referred to as a cathartic or a purgative.

  • bulk l. — hydrophilic, indigestible substances that absorb water and swell to form an emollient gel. The distention of the intestine stimulates defecation.
  • contact l. — see stimulant laxative (below).
  • emollient l. — the fecal softeners; act without being changed and simply aid expulsion by softening and lubricating. Called also lubricant laxative.
  • lubricant l. — see emollient laxative (above).
  • stimulant l. — stimulate accumulation of water and electrolytes in the colon, increasing intestinal motility. Called also contact laxative.
Wikipedia:

Laxative

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Laxatives (also known as purgatives or aperients) are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and bowel examinations, and may be supplemented by enemas in that circumstance. Sufficiently high doses of laxatives will cause diarrhea. Laxatives work to hasten the elimination of undigested remains of food in the large intestine and colon.[1]


There are several types of laxatives, listed below. Some laxatives combine more than one type of active ingredient to produce a combination of the effects mentioned. Laxatives may be oral or in suppository form.

Constipation with no known organic cause, i.e. no medical explanation, exhibits gender differences in prevalence: females are more often affected than males.[2] Not surprisingly, some advertisers promote their brands as being more feminine and thereby tailor their message to the market. The way laxatives function in males and females, however, does not exhibit significant differences.

Contents

Foods

Some vegetables and foods can be eaten to cure constipation and act as laxatives, although the effectiveness may vary. These include:

Bulk-producing agents

Also known as bulking agents or roughage, these include dietary fiber. Bulk-producing agents cause the stool to be bulkier and to retain more water, as well as forming an emollient gel, making it easier for peristaltic action to move it along. They should be taken with plenty of water. Bulk-producing agents have the gentlest of effects among laxatives and can be taken just for maintaining regular bowel movements.

Stool softeners / Surfactants

  • Site of Action: Small and large intestine
  • Onset of Action: 12 – 72 hours
  • Examples: docusate (Colace, Diocto)

These enable additional water and fats to be incorporated in the stool, making it easier to move along. Their strength is between that of the bulk producers and the stimulants, and they can be used for patients with occasional constipation or those with anorectal conditions for whom passage of a firm stool is painful.

Lubricants / Emollient

  • Site of Action: Colon
  • Onset of Action: 6 – 8 hours

These simply make the stool slippery, so that it slides through the intestine more easily. An example is mineral oil, which also retards colonic absorption of water, softening the stool. Mineral oil may decrease the absorption of fat-soluble vitamins and some minerals.

Hydrating agents (osmotics)

These cause the intestines to hold more water within, softening the stool. There are two principal types, saline and hyperosmotic.

Saline

Saline laxatives attract and retain water in the intestinal lumen, increasing intraluminal pressure and thus softening the stool. They will also cause the release of cholecystokinin, which stimulates the digestion of fat and protein. Saline laxatives may alter a patient's fluid and electrolyte balance.

Sulfate salts are considered the most potent.[citation needed]

Hyperosmotic agents

Lactulose works by the osmotic effect, which retains water in the colon, lowering the pH and increasing colonic peristalsis. Lactulose is also indicated in Portal-systemic encephalopathy. Glycerin suppositories work mostly by hyperosmotic action, but also the sodium stearate in the preparation causes local irritation to the colon.

Solutions of polyethylene glycol and electrolytes (sodium chloride, sodium bicarbonate, potassium chloride, and sometimes sodium sulfate) are used for whole bowel irrigation, a process designed to prepare the bowel for surgery or colonoscopy and to treat certain types of poisoning. Brand names for these solutions include GoLytely, GlycoLax, CoLyte, Miralax, NuLytely, and others.

Effectiveness

For adults, a randomized controlled trial found PEG [MiraLax or GlycoLax] 17 grams once per day better than tegaserod 6 mg twice per day.[3] A randomized controlled trial found greater improvement from 2 sachets (26 grams) of PEG versus 2 sachets (20 grams) of lactulose [4]. 17 grams/day of PEG has been effective and safe in a randomized controlled trial for six months.[5] Another randomized controlled trial found no difference between sorbitol and lactulose [6].

For children, PEG was found to be more effective than lactulose.[7]

Stimulant / Irritant

  • Site of Action
Colon
Examples
Onset of Action Laxative Name
6 – 8 hours
6 – 10 hours
2 – 6 hours
15 min - 1 hour

These stimulate peristaltic action and can be dangerous under certain circumstances. Long term use can lead to 'cathartic colon'.[8] Stimulant laxatives act on the intestinal mucosa, or nerve plexus; they also alter water and electrolyte secretion. They are the most severe among laxatives and should be used with care. Castor oil may be preferred when more complete evacuation is required.

Castor oil

  • Site of Action
Small intestine

Castor oil acts directly on intestinal mucosa or nerve plexus and alters water and electrolyte secretion. It is converted into ricinoleic acid (the active component) in the gut.

Serotonin agonist

Tegaserod is a motility stimulant that works through activation of 5-HT4 receptors of the enteric nervous system in the gastrointestinal tract. However caution must be taken due to potentially harmful cardiovascular side-effects.

Zelnorm (market name for Tegaserod) was discontinued from marketing on March 30, 2007[9] but is still available for prescription under tight controls.

Uses

  • Bowel preparation
  • Chronic constipation
  • Chronic immobility

Problems with use

Laxative Abuse

Laxative abuse is potentially serious since it can lead to intestinal paralysis,[citation needed] Irritable Bowel Syndrome (IBS),[10] pancreatitis,[citation needed] renal failure,[11][12] and other problems, even though recovery is possible with proper treatment.

Laxative gut

Physicians generally warn against the chronic use of stimulant laxatives due to concern that chronic use causes the colonic tissues to get worn out over time and not be able to expel feces due to long term overstimulation. The evidence for this was never too strong, and it was always unclear whether the elongated and poorly moving colon of a patient with chronic constipation was a result of or was just a cause for patients' use of stimulant laxatives. A common finding in patients who have used stimulant laxatives is a brown pigment deposited in the intestinal tissue, known as Melanosis coli.

Eating disorders

Laxatives are often used by people with an eating disorder. In many cases of bulimia nervosa the patient will abuse laxatives in an attempt to get rid of the calories, to purge themselves of food in the intestines before it becomes digested and absorbed by the body. This will not work, because laxatives hasten the elimination of undigested remains of food in the large intestine and colon. The large intestine and colon do not digest food. They just collect the undigested remains and hold it and absorb water until it is defecated. Weight loss may be felt, but this is only temporary due to the fact that the person has expelled much of the fluids from their body. The common question of whether or not chronic diarrhoea associated with laxative use can promote some degree of true weight loss remains unknown. In any case, this type of laxative misuse causes water to be lost more rapidly than is healthy, potentially leading to dehydration and electrolyte imbalance. Prolonged usage of laxatives will actually cause constipation. The sensation of bloating can be significant due to excessive water retention, leading to people with eating disorders to increase the dosage of the laxatives, resulting in dependency and further complicating the constipation. Abusing stimulant-type laxatives can lead to permanent impairment of the bowels, and the constipation problem becomes irreversible. In addition, blood can develop in stools, and excessive blood loss can result in anemia. Patients recovering from laxative abuse often have several months of problematic water retention, resulting in temporary weight gain (not noticeable on the exterior), and sometimes "pitting" edema (in which pressing on the skin leaves an indentation).

See also

References

  1. ^ [1]
  2. ^ Chang L, Toner B, Fukudo S, Guthrie E, Locke G, Norton N, Sperber A (2006). "Gender, age, society, culture, and the patient's perspective in the functional gastrointestinal disorders". Gastroenterology 130 (5): 1435–46. doi:10.1053/j.gastro.2005.09.071. PMID 16678557. 
  3. ^ Di Palma JA, Cleveland MV, McGowan J, Herrera JL (2007). "A randomized, multicenter comparison of polyethylene glycol laxative and tegaserod in treatment of patients with chronic constipation". Am. J. Gastroenterol. 102 (9): 1964–71. doi:10.1111/j.1572-0241.2007.01365.x. PMID 17573794. 
  4. ^ Attar A, Lémann M, Ferguson A, Halphen M, Boutron M, Flourié B, Alix E, Salmeron M, Guillemot F, Chaussade S, Ménard A, Moreau J, Naudin G, Barthet M (1999). "Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation.". Gut 44 (2): 226–30. PMID 9895382. 
  5. ^ Dipalma JA, Cleveland MV, McGowan J, Herrera JL (2007). "A randomized, multicenter, placebo-controlled trial of polyethylene glycol laxative for chronic treatment of chronic constipation". Am. J. Gastroenterol. 102 (7): 1436–41. doi:10.1111/j.1572-0241.2007.01199.x. PMID 17403074. 
  6. ^ Lederle F, Busch D, Mattox K, West M, Aske D (1990). "Cost-effective treatment of constipation in the elderly: a randomized double-blind comparison of sorbitol and lactulose.". Am J Med 89 (5): 597–601. doi:10.1016/0002-9343(90)90177-F. PMID 2122724. 
  7. ^ "BestBETs: Is polyethylene glycol safe and effective for chro...". http://www.bestbets.org/cgi-bin/bets.pl?record=00901. Retrieved 2007-09-06. 
  8. ^ Joo J, Ehrenpreis E, Gonzalez L, Kaye M, Breno S, Wexner S, Zaitman D, Secrest K (1998). "Alterations in colonic anatomy induced by chronic stimulant laxatives: the cathartic colon revisited.". J Clin Gastroenterol 26 (4): 283–6. doi:10.1097/00004836-199806000-00014. PMID 9649012. 
  9. ^ FDA Announces Discontinued Marketing of GI Drug, Zelnorm, for Safety Reasons
  10. ^ "Laxative Abuse: Some Basic Facts" (PDF). National Eating Disorders Association. 2005. http://www.nationaleatingdisorders.org/nedaDir/files/documents/handouts/Laxative.pdf. Retrieved 2008-09-07. 
  11. ^ Copeland P (1994). "Renal failure associated with laxative abuse". Psychother Psychosom 62 (3-4): 200–2. doi:10.1159/000098619. PMID 7531354. 
  12. ^ Wright L, DuVal J (1987). "Renal injury associated with laxative abuse". South Med J 80 (10): 1304–6. doi:10.1097/00007611-198710000-00024. PMID 3660046. 

External links


Translations:

laxative

Top
Laxative

Dansk (Danish)
adj. - afførende
n. - afførende middel, laksativ

Nederlands (Dutch)
laxatief, laxerend, laxeermiddel

Français (French)
adj. - laxatif
n. - laxatif

Deutsch (German)
n. - Abführmittel
adj. - abführend

Ελληνική (Greek)
n. - καθαρτικό, υπακτικό, καθάρσιο
adj. - υπακτικός, καθαρτικός

Italiano (Italian)
purgante

Português (Portuguese)
n. - laxante (m)
adj. - laxativo

Русский (Russian)
слабительное средство, слабительный

Español (Spanish)
adj. - laxante, purgante
n. - laxante, purgante

Svenska (Swedish)
n. - laxermedel
adj. - (läk.) lösande, avförande, laxer-

中文(简体)(Chinese (Simplified))
通便的, 不简洁的, 泻药, 缓泻药

中文(繁體)(Chinese (Traditional))
adj. - 通便的, 不簡潔的
n. - 瀉藥, 緩瀉藥

한국어 (Korean)
adj. - 완화제의, 대변을 나오게 하는
n. - 완화제 , 하제

日本語 (Japanese)
n. - 下剤, 通じ薬
adj. - 通じを付ける

العربيه (Arabic)
‏(الاسم) مسهل, ملين, فالت, جامح بمعنى غير مكبوح للألسنه (صفه) مسهل, ملين‏

עברית (Hebrew)
adj. - ‮גורם לשלשול‬
n. - ‮(חומר) משלשל‬


 
 

 

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