Medications for Constipation and IBS-C Treatment

doctor with patient
John Fedele/Blend Images

In the past, prescription medications for treating chronic constipation and constipation-predominant irritable bowel syndrome (IBS-C) were limited. Fortunately, this is changing and a number of prescription medications are available by for treating chronic constipation.

Amitiza (lubiprostone)

Amitiza is approved by the FDA for the treatment of IBS-C, as well as for chronic idiopathic constipation (CIC). Amitiza works by increasing the number of fluids in the intestines and therefore easing the passage of stools.

The medication operates on a cellular level as it targets (activates) proteins involved in transporting chloride, thus Amitiza is known as a chloride channel activator. Most people who take Amitiza will experience symptom relief within 24 hours. 

You should not take Amitiza if you have a bowel obstruction, experience severe diarrhea, or are pregnant or breastfeeding. 


Lactulose is an osmotic laxative that is used for the treatment of constipation. It is sold under a variety of brand names. These include Cephulac, Chronulac, Constilac, Cholac, Constulose, Duphalac, Enulose, Generlac, and Kristalose. 

Lactulose is a man-made sugar that is broken down by bacteria in the intestines, a process that pulls more water into the colon. This increase in water softens, increases, and normalizes the stool. The higher volume of stool helps to stimulate colon motility and therefore encourages a bowel movement.

Lactulose is generally recommended to be used on a short-term basis. This is typically not a doctor's first choice as it is poorly tolerated (causing more bloating and gas) and is rarely more effective than other options.

Before taking lactulose, make sure that your doctor knows if you are scheduled for surgery, suffer from diabetes, or are pregnant or breastfeeding. 

Linzess (linaclotide)

Linzess has been approved by the FDA for the treatment of IBS-C and CIC. In Europe, the medication is called Constella and is approved for the treatment of IBS-C.

The medication is characterized as a guanylate cyclase-C agonist. It is thought to work by increasing the amount of fluid in the large intestine resulting in increased number of bowel movements and decreased abdominal pain.


Prucalopride is classified as a 5-HT agonist as it activates receptors for the neurotransmitter serotonin (5-HT). Unfortunately, prucalopride is not yet approved of for use by the FDA and is not available in the U.S. It is available in Europe and Canada, with some limitations on its prescription. 


Unlike the other medications profiled on this page, Miralax does not require a prescription. However, doctors frequently recommend Miralax due to its effectiveness in easing constipation. Miralax draws water into the stool, softening it and inducing the urge for a bowel movement. 

Zelnorm (tegaserod)

Zelnorm is a medication that was designed to treat IBS-C and CIC. It too works by increasing the amount of the neurotransmitter serotonin in the cells of the gut’s own nervous system.

Due to identified serious health risks, the medication is only available on an emergency basis. Its prescription must be authorized directly by the FDA. 

A Note About Antidepressants

Antidepressants are not approved as a treatment for constipation. However, due to the high rate of depression in patients with IBS and the fact that antidepressants can have effective anti-pain properties, a doctor may prescribe an antidepressant to an individual dealing with IBS-C.

The antidepressants chosen for a person who experiences constipation would be from the class called selective serotonin reuptake inhibitors (SSRIs). These are less likely to cause constipation. Examples of SSRIs include Celexa, Lexapro, Prozac, Paxil, and Zoloft. 

View Article Sources