New drug for chronic constipation

FDA Consumer, May-June, 2006

The FDA has approved Amitiza (lubiprostone), the first drug of its chemical type, for the treatment of chronic constipation of unknown cause in adults. Approved in January 2006, Amitiza is available as capsules for use by adults to treat "idiopathic" constipation cases not caused by other diseases or by use of medications.

Chronic idiopathic constipation is generally defined as infrequent and difficult passage of stool. It's one of the most common disorders suffered by Americans. This condition affects women more often than men and also affects people older than 65 more frequently. Symptoms of chronic idiopathic constipation are abdominal pain and discomfort, bloating, straining, and hard stools.

Amitiza increases the intestinal fluid secretion, which helps ease the passage of stool and helps alleviate symptoms. The FDA based its decision to approve Amitiza on results from two clinical trials, which were conducted in patients with, on average, less than three spontaneous bowel movements a week with symptoms of constipation for at least six months before entry into the studies.

The studies demonstrated that subjects treated with Amitiza had a higher frequency of bowel movements in the first week than the subjects who received a phony pill. In both studies, results similar to those in Week 1 were also observed in Weeks 2, 3, and 4 of therapy.

The most common adverse events reported in the trials included headache, nausea, diarrhea, abdominal pain, and distension. Whether these events are related to the drug is not known at this time. Amitiza should be taken twice a day with food. Physicians and patients should periodically assess the need for continued treatment.

Amitiza is marketed by Sucampo Pharmaceuticals Inc., Bethesda, Md., and by Takeda Pharmaceuticals America, Lincolnshire, Ill.