The FDA ( Food and Drug Administration ) has approved Amitiza ( Lubiprostone ) for the treatment of irritable bowel syndrome with constipation ( IBS-C ) in adult women aged 18 and over. There is currently no prescription drug therapy for IBS-C. With this approval, Amitiza becomes the only FDA-approved medical treatment for irritable bowel syndrome with constipation available in the United States.
Irritable bowel syndrome is a disorder characterized by cramping, abdominal pain, bloating, constipation, and diarrhea. IBS causes a great deal of discomfort and distress to its sufferers. It affects at least twice as many women as men.
The safety and efficacy of Amitiza was established in two major studies involving 1,154 patients diagnosed with irritable bowel syndrome with constipation. The majority of the patients studied were women ( approximately 8 percent were men ). Patients enrolled in the studies were experiencing at least mild abdominal discomfort or pain that was associated with at least two of the following additional symptoms: 1) fewer than 3 spontaneous bowel movements per week ( that did not result from laxative use ); 2) hard stools; or 3) moderate or severe straining with bowel movements.
In the studies some patients received Amitiza and others were given a placebo.
More patients treated with Amitiza reported that their IBS symptoms were moderately or significantly relieved over a 12 week treatment period than patients who received placebo. The safety of long term treatment was assessed in a study in which all patients were treated with Amitiza for a duration that ranged 9 to 13 months.
The efficacy of Amitiza in men was not conclusively demonstrated for irritable bowel syndrome with constipation.
Amitiza, like most prescription medications, is accompanied by some side effects. Common side effects of Amitiza include nausea, diarrhea, and abdominal pain. Other rare side effects include urinary tract infections, dry mouth, syncope, peripheral edema, dyspnea, and heart palpitations.
Amitiza should be taken twice-a-day in 8 microgram doses with food and water. Patients and their health care professionals should periodically assess the need for continued therapy.
Amitiza is not approved for use in children and men. It is not to be administered to patients suffering from severe diarrhea or patients with known or suspected bowel obstructions. Its safety and efficacy has not been established in patients with renal or hepatic impairment, pregnant, or nursing mothers.
Amitiza is also approved for the treatment of chronic idiopathic constipation, but the dose for that indication is higher, 24 micrograms twice a day.
Source: FDA, 2008
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