The FDA approved lubiprostone (Amitiza) (Takeda Pharmaceuticals), the first selective chloride channel activator approved for the treatment of adults with chronic idiopathic constipation not caused by other diseases or by medications.

Lubiprostone is available as capsules and is taken twice daily with food.

The new drug works by increasing intestinal fluid secretion to help ease the passage of stool and helps alleviate symptoms associated with chronic idiopathic constipation. The FDA approved lubiprostone based on the results of two clinical trials that showed patients taking the drug had a higher frequency of bowel movements in the first week than the subjects taking placebo. In both studies, results similar to those in the first week were also observed in the following 3 weeks of treatment. Three other studies showed that lubiprostone decreased constipation severity, abdominal bloating, and discomfort over 6 to 12 months of use.

The most common adverse effects associated with lubiprostone were headache, nausea, diarrhea, abdominal pain, and distension.

Lubiprostone is contraindicated in patients with a history of mechanical gastrointestinal obstruction. The safety of the drug during pregnancy is not known. Women planning to take the medication should confirm they are not pregnant prior to starting the medication.