March 26, 2017
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Laxatives For Constipation (cont.)

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Pros and precautions for using stimulant laxatives

Stimulant laxatives are fast-acting laxatives that induce bowel movements by increasing the contraction of muscles in the intestines, and are effective when used on a short-term basis. Examples of stimulant laxatives include:

  • Aloe
  • Cascara
  • Senna compounds
  • Bisacodyl
  • Castor oil

Bisacodyl: Bisacodyl (Dulcolax, Correctol) is available OTC in oral pill form and as a suppository or enema. The oral form takes 6 to 10 hours to work. Bisacodyl is commonly used in cleansing the colon for colonoscopies, barium enemas, and intestinal surgeries. While effective for occasional constipation, bisacodyl should not be taken for more than a week, and a doctor should supervise repeated use.

Senna, cascara sagrada, and casanthranol: Other stimulant laxatives include senna (Ex-Lax, Senokot), cascara sagrada (Nature's Remedy), and casanthranol. These laxatives are converted by the bacteria in the colon into active compounds, which then stimulate the contraction of colon muscles. After taking these products orally, bowel movements occur quickly, after only 8 to 24 hours. Prolonged, chronic use of these laxatives can cause the lining of the colon to become darker than normal (melanosis coli) due to the accumulation of a pigment (melanin).

Castor oil: Castor oil (an ingredient of Purge Concentrate) is a liquid stimulant laxative that works in the small intestine. It causes the accumulation of fluid in the small intestine and promotes evacuation of the bowels. Castor oil should not be taken with food, although juice or other flavored liquids can help hide its unpleasant taste. This laxative works rather quickly, usually within 2 to 6 hours. Castor oil is usually used to cleanse the colon for surgery, barium enema, or colonoscopy. The absorption of nutrients and minerals by the small intestine can be impaired by the frequent use of castor oil. This medicine is not recommended for the repeated treatment for constipation.

Precautions for stimulant laxatives

  • The intensity of the action of stimulant laxatives is dose related. A large dose of any stimulant laxative can produce serious adverse effects.
  • Side effects include severe cramps, excess fluid loss and dehydration, blood electrolyte disturbances such as low levels of blood potassium (hypokalemia), and malnutrition with chronic use.
  • There is concern that chronic, long-term use of stimulant laxatives can lead to loss of colon function (cathartic colon). After years to decades of frequent use of stimulant laxatives, the nerves of the colon slowly disappear, the colon muscles wither, and the colon becomes dilated. Consequently, constipation may become increasingly worse and unresponsive to laxatives. It is not clear, however, which comes first; a progressive decrease in colon function that leads to the use of stimulant laxatives, or the use of laxatives that leads to a decrease in colon function. Nevertheless, long term use of stimulant laxatives usually is reserved for use after other treatments have failed.

Pros and precautions for using saline laxatives and osmotic laxatives

  • The active ingredients in saline laxatives are mostly magnesium, sulfate, citrate, and phosphate ions. These ions draw water into the intestines. The additional water softens the stool, increases pressure within the intestines, and increases intestinal contractions resulting in the discharge of softer stool. Fleet Phospho-Soda, milk of magnesia, and magnesium citrate are examples of saline laxatives.
  • Oral doses of saline laxatives should be taken with one to two 8 ounce glasses of water. The onset of bowel response is usually 1/2 to 3 hours after consuming the laxative. Small doses are sometimes recommended for the treatment of occasional constipation, while larger doses can produce complete evacuation of the intestine. Complete cleansing of the bowel is useful in preparing for colonoscopy, sigmoidoscopy, and barium enema.
  • The active ingredient in osmotic-type laxatives such as GoLYTELY, GlycoLax, and MiraLax is polyethylene glycol (PEG). These work by holding water in the stool to soften the stool and increasing the number of bowel movements. Osmotic-type laxatives are often used to cleanse the bowel prior to colonoscopies or colon surgery.

Precautions for saline and osmotic laxatives

  • Since there may be some absorption of the active ingredients from the intestines into the blood circulation, saline laxatives should not be used in certain individuals. Individuals with impaired kidney function should not use laxatives containing magnesium or phosphate salts. Excess accumulation of magnesium and phosphate in the blood of these individuals can lead to toxicity. Those who need to limit their sodium intake, such as those with congestive heart failure, kidney disease, and high blood pressure, should not use laxatives that contain sodium.
  • Side effects of osmotic-type laxatives include nausea, abdominal cramping, or gas.
  • People who have a history of abdominal surgery or bowel obstruction should consult their doctor before using this medication.
  • Caution is advised when using this drug in the elderly because they may be more sensitive to its side effects, especially diarrhea.

Pros and precautions for using enemas and suppositories

Rectally administered enemas and suppositories are commonly used to cleanse the rectum and the sigmoid colon (the part of the colon closest to the rectum) prior to surgery, childbirth, and flexible sigmoidoscopy. Enemas and suppositories are used to relieve constipation and rectal fecal impaction (blockage of the rectum by hard, compacted stool). They can also be used in conjunction with oral laxatives in cleansing the colon in preparation for barium enema studies. Some suppositories contain stimulant laxatives.

Enemas and suppositories include docusate (Microenema), bisacodyl (Dulcolax Suppository), and sodium phosphate (Fleet Enema). These products are intended for occasional use and are not recommended as a chronic laxative regimen unless directed by a physician.

Individuals should carefully follow instructions in using enemas. The person should lie on the left side with the knees bent. The enema solution should be inserted slowly into the rectum. The person should retain the solution in the rectum until definite rectal pressure and the urge to have a bowel movement are felt. Evacuation usually occurs within minutes to an hour.

Precautions for using enemas and suppositories

  • Soapsuds enemas can cause rectal irritation and sometimes rectal gangrene and are not recommended.
  • Enema solutions can cause fluid and electrolyte disturbances in the blood if used on a chronic basis.
Medically Reviewed by a Doctor on 11/10/2016

Source: MedicineNet.com
http://www.medicinenet.com/laxatives_for_constipation/article.htm

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