The FDA approved Amitiza (lubiprostone), the first drug of its chemical type, for the treatment of chronic constipation in the adult population where there is no known cause for the condition. The product will be 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 and is one of the most common disorders suffered by Americans. This condition affects women more often than men and also affects older patients after the age of 65 more frequently. Symptoms of chronic idiopathic constipation are abdominal pain and discomfort, bloating, straining, and hard stools.
Amitiza works by increasing the intestinal fluid secretion, which helps ease the passage of stool and helps alleviate symptoms associated with chronic idiopathic constipation. FDA based its decision to approve Amitiza on the results from two clinical trials, which were conducted in patients with, on average, less than 3 spontaneous bowel movements per week with symptoms of constipation for at least 6 months prior to 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 placebo subjects. In both studies, results similar to those in Week 1 were also observed in Weeks 2, 3, and 4 of therapy. In addition, three long-term studies showed that Amitiza decreased constipation severity, abdominal bloating and discomfort over 6-12 months of use.
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 present.
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, IL.