Amitiza : An FDA Approved Medication
Also known as Lubiprostone
The trade name of lubiprostone is Amitiza, an FDA approved constipation medication for treating chronic, idiopathic constipation. Amitiza was approved in mid-2006. Clinical trials have shown taking Amitiza increases the speed at which food moves through the intestine, increases the frequency of bowel movements, and also softens the stool for an improvement in consistency.
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Amitiza is one of the only FDA-approved constipation remedies for treating chronic constipation. One of the problems of this drug for patients is that it is quite expensive, being a new medication and the only one of its kind.
Stimulation of water entry into the intestine
How does Amitiza work? The cells of your body form an impenetrable barrier to substances like water. In other words, water doesn't enter through your skin into your body, or from your gastrointestinal tract into the tissues. Any water that goes from the interior to the exterior or vice versa must be transported by special protein channels. The same is true of water entering the intestinal lumen (or cavity). Moreover, the channels that control water entry into the lumen use calcium ions to assist the water molecules in passing. Amitiza is a stimulator of the calcium channels, which prompts it to transport more water from within the tissues into the intestinal lumen. The result seems to be increased lubrication of the intestinal cavity which helps food pass.
Amitiza significantly reduces constipation
Is Amitiza effective? In the original study for approving the constipation medication, Amitiza was shown to significantly reduce constipation when taken twice daily compared to a population who did not take it. For example, in one metric, the researchers found that 57% of those taking Amitiza had a bowel movement within the first 24 hours, whereas only 37% of those on a placebo did. The beneficial effects continued up to 48 weeks, which is almost a year.
Well-tolerated but with a few side-effects
The drug is reported to be well tolerated as a constipation medication, especially by the elderly. Although there were some adverse side effects such as nausea and diarrhea, ironically. In summary, Amitiza seems to be fulfilling its promise as a drug that can relieve the symptoms of constipation. The prospective patient should understand that Amitiza does not cure constipation, because the underlying cause is not eliminated. By virtue of its actions, Amitiza merely relieves the symptom of whatever its fundamental cause.
The only drug of its kind
There have been several other constipation medications which have gone through either preclinical or clinical trails for treating chronic constipation, however, Amitiza is thus far the only one in the United States to win approval. As the only drug of its kind, the cost may be prohibitive, especially when compared against more traditional treatments such as high dose insoluble fiber or laxatives.
The American College of Gastroenterology
In a review article by Eoff and Lembo in the Journal of Managed Care Pharmacy, the authors noted that the American College of Gastroenterology does not recommend any anti-constipation chemical agent prior to 2005, which is a year before lubiprostone was released.
Sources:
Fox-Orenstein et al, Update on constipation: One treatment does not fit all, Cleveland Clinic Journal of Medicine, 2008; 75(11):813-824
Eoff and Lembo, Optimal Treatment of Chronic Constipation in Managed Care, Journal of Managed Care Pharmacy, 2008; 14(9a):Supplement