The U.S. Food and Drug Administration has approved Linzess (linaclotide) to treat chronic idiopathic constipation and to treat irritable bowel syndrome with constipation in adults. 

The once a daily pill is designed to be taken on an empty stomach, at least 30 minutes before the first meal of the day. The FDA said the durg helps relieve constipation by helping bowel movements occur more often and may also help ease abdominal pain.

"No one medication works for all patients suffering from these gastrointestinal disorders," said Victoria Kusiak, deputy director of the Office of Drug Evaluation III in FDA's Center for Drug Evaluation and Research. "With the availability of new therapies, patients and their doctors can select the most appropriate treatment for their condition."

Researchers tested the safety and effectiveness of Linzess in two, double-blind studies. A total of 1,604 patients were randomly assigned to take 290 micrograms of Linzess or a placebo for at least 12 weeks. Results showed Linzess was more effective in reducing the amount of abdominal pain and increasing the number of complete spontaneous bowel movements compared with placebo.

The safety and effectiveness of Linzess for the management of chronic idiopathic constipation also were established in two, double-blind studies. A total of 1,272 patients were randomly assigned to take Linzess at doses of 145 mcg or 290 mcg or a placebo for 12 weeks. Results from these studies showed patients taking Linzess experienced more complete spontaneous bowel movements than those taking the placebo. The 290 mcg dose is not approved for chronic constipation because studies indicated it was no more effective than the 145 mcg dose.

Linzess is approved with a Boxed Warning to alert patients and health care professionals that the drug should not be used in patients 17 years of age and younger. The most common side effect reported in during the clinical studies was diarrhea.

According to the National Institutes of Health, about 63 million people are affected by chronic constipation. 

Chronic idiopathic constipation is when people experience persistent constipation and do not respond to standard treatment. 

Additionally, an estimated 15.3 million people are affected by irritable bowel syndrome. IBS-C is a subtype characterized mainly by abdominal pain and by hard or lumpy stools at least 25 percent of the time and loose or watery stools less than 25 percent of the time.