A number of medicines are available to treat constipation.
This is the second of a 2-part Patient Page on constipation. Part 1 provided a general overview and was published in JAMA on January 12, 2016.
Changing your bowel habits and increasing dietary fiber can help prevent constipation (see Part 1). But if you have tried these steps and still have constipation, a variety of laxatives are available. Some may require a prescription, but many are available over the counter. Although laxatives can cause minor side effects such as diarrhea and cramps, they are considered effective and safe.
Laxatives work in different ways. In general, they belong to 1 of 4 groups.
Bulk-forming laxatives include
Psyllium (Konsyl, Metamucil, Perdiem)
Calcium polycarbophil (Fibercon, Fiber-Lax)
Wheat dextrin (Benefiber)
You should take bulk laxatives with plenty of fluid. You should also increase the dose slowly. This can help reduce gas and cramping.
Hyperosmolar laxatives include
Polyethylene glycol (Miralax, Glycolax)
Lactulose and sorbitol are equally effective but can cause gas and bloating. Of these, sorbitol costs less. Polyethylene glycol does not cause gas. It is also available in the United States without a prescription.
Saline laxatives include
Magnesium hydroxide (Milk of Magnesia)
Magnesium citrate (Evac-Q-Kwik)
These work like hyperosmolar laxatives but often are more effective. But you should take them no more than twice a week. Also, you should use them with caution if you have kidney disease.
Stimulant laxatives include
Senna (Ex-Lax, Senokot, Castoria)
Bisacodyl (Correctol, Doxidan, Dulcolax)
All are available without prescription. Generic versions are equally effective and cost less. Overuse of stimulant laxatives can cause side effects. But they are safe and effective when used correctly and may be used regularly.
Lubiprostone (Amitiza) and linaclotide (Linzess) are prescription medicines that increase fluid content in the bowels. Both are expensive but may be recommended if other treatments have not worked.
Several treatments that have been commonly used should be avoided. These include
Emollients (mineral oil; docusate). These soften stool by adding moisture. But laxatives are safer.
Some natural products contain ingredients found in laxatives. But their dose and purity may not be carefully controlled.
Homemade enemas containing soap suds, hydrogen peroxide, or household detergents. These can irritate the bowel.
National Institute of Diabetes and Digestive and Kidney Diseaseswww.niddk.nih.gov/health-information/health-topics/digestive-diseases/constipation/Pages/overview.aspx
To find this and previous JAMA Patient Pages, go to the Patient Page link on JAMA’s website at www.jama.com/. Spanish translations are available in the supplemental content tab.
Conflict of Interest Disclosures: Dr Wald has completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and reports advising Takeda Sucampo, Ironwood, Actavis, Entera Health, and Forest Laboratories.
Source: Wald A. Constipation: advances in diagnosis and treatment. JAMA. doi:10.1001/jama.2015.16994.
Wald A. Treating Constipation With Medications. JAMA. 2016;315(12):1299. doi:10.1001/jama.2015.17993