Table of Contents
- Constipation definition and facts
- What is constipation?
- What causes constipation?
- Medications that cause constipation
- Other causes of constipation
- What are constipation symptoms?
- What tests help diagnose the cause of severe constipation?
- How are the causes of constipation treated?
- Dietary fiber, bulk-forming and lubricant laxatives, and stool softeners
- Over-the-counter (OTC) laxatives
- Biofeedback, exercise, and surgery
- Prescription drugs to treat constipation
- Home remedies for constipation relief
- When should I seek medical care for chronic constipation?
- What is new in the treatment of constipation?
Quick Guide19 Constipation Myths and Facts
Prescription drugs to treat constipation
Lubiprostone (Amitiza) is a selective chloride channel activator that increases secretion of chloride ions from the cells of the intestinal lining into the intestinal lumen. Sodium ions and water then follow the chloride ions into the lumen, and the water softens the stool. The FDA approved lubiprostone for the treatment of chronic constipation in both men and women in February 2006. At a dose of 24 micrograms twice a day, lubiprostone significantly and promptly increased bowel movements, improved stool consistency, and decreased straining. The most common side effect of initial clinical studies was mild to moderate nausea in 32% of patients treated with lubiprostone, compared to 3% of the controls.
Linaclotide (Linzess) is an oral drug that is not absorbed from the intestine. It stimulates the cells lining the small intestine to secrete fluid into the intestine. The increase in fluid secretion leads to an increased number of bowel movements. In addition, when it is associated with the abdominal pain of IBS, the pain also is reduced. Although the improvement in pain may be due to the improvement, linaclotide has been shown also to reduce the sensitivity of intestinal pain nerves, and this mechanism of action also may account for the decrease in pain.
Linaclotide is moderately effective, and its effectiveness depends on how a favorable response is defined. In the studies leading up to its approval, linaclotide was associated with a predefined response of an increase in bowel movements and a decrease in pain in approximately one-third of patients as compared with 17% of patients who received placebo. The response was better when pain and constipation were considered separately, with responses of approximately 50% for either.
The only common side effect of linaclotide is diarrhea. It should not be used in children below the age of six because of serious toxicity (death) to very young mice in animal studies, and should be avoided in children ages six through 17.
Miscellaneous drugs to treat constipation
Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs to treat the condition.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostol (Cytotec) is a drug used primarily for preventing stomach ulcers caused by nonsteroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostol is effective in treating it short term. Misoprostol is expensive, and it is not clear if it will remain effective and safe with long-term use. Therefore, its role in treatment remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few important side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for to treat the condition. Although it is difficult to recommend them specifically just for the management it, they might be considered for patients who are constipated and are overweight, have gout, or need protection from nonsteroidal anti-inflammatory drugs.
Prucalopride (Resolor) is an oral drug. It is the only approved drug belonging to a new class of drugs, the dihydro-benzofuran-carboxamides. It attaches to receptors within the intestinal wall that promote intestinal motility, that is, contraction of the muscles of the wall that move stool through the intestine.
Prucalopride is effective in patients with chronic constipation. Randomized, placebo-controlled studies have shown that at maximum doses it increases the number of stools per week by one in approximately 50% of patients compared with approximately 25% of patients given placebo. It increases the number of stools per week to more than 3 in approximately 25% of patients compared with approximately 12% of patients given placebo. Most of the patients in the studies were having less than one stool per week before starting prucalopride.
The most common side effects of prucalopride are headache and gastrointestinal symptoms including nausea, diarrhea, and abdominal pain. These symptoms usually are mild, frequently resolve with continued treatment, and infrequently cause patients to discontinue treatment.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
National Institutes of Diabetes and Digestive and Kidney Diseases. "Constipation."
National Institute of Diabetes and Digestive and Kidney Diseases. "Eating, Diet, & Nutrition for Constipation.