William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Constipation facts
- What is constipation?
- What causes constipation?
- Medications that cause constipation
- Other causes of constipation
- What are constipation symptoms?
- How is constipation diagnosed (evaluated)?
- Exams and tests
- Imaging studies and other tests
- What treatments are available for constipation?
- Dietary fiber and bulk-forming laxatives to treat constipation
- Other laxatives to treat constipation
- Other laxatives and OTC products to treat constipation
- Prescription drugs to treat constipation
- Other treatments for constipation
- What is the approach to the evaluation and treatment of constipation?
- When should I seek medical care for chronic constipation?
- What is new in the treatment of constipation?
- Pictures of Constipation Myths and Facts - Slideshow
- Pictures of Irritable Bowel Syndrome (IBS) - Slideshow
- Pictures of What's Causing Your Pelvic Pain - Slideshow
Other laxatives to treat constipation
Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages.
The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins. This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin (Coumadin) and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners)
Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (for example, Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water within the stool softens the stool, although studies have not shown docusate to be consistently effective in relieving constipation. Stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen.
Although docusate generally is safe, it may increase the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (for example, after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (for example, Kristalose), sorbitol, and polyethylene glycol (for example, MiraLax), and they are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects.
Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related and less with polyethylene glycol. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Find out what women really need.