Amitiza or lubiprostone is a relatively new treatment for severe constipation predominant Irritable Bowel Syndrome in women.
The trials of the drug didn't include men so the treatment licence is currently only for women.
It is used for both chronic idiopathic constipation as well as IBS-C.
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Also known as Lubiprostone, this prostone drug is a ClC-2 chloride channel activator.
CIC-2 channels are chloride channels found in the membranes of human enterocytes or 'cells that line the gut'.
The channels increase the secretion of fluids and electrolytes softening the stool in constipation and allowing the passage of stool through your gut.
Symptoms of constipation including abdominal pain and bloating can settle with this treatment.
Lubiprostone comes as 8 mcg and 24 mcg capsules and should be taken with food and water.
A starting dose of 8 mcg twice a day in IBS-C, the drug dose can be increased to 24 mcg a day can be taken if necessary.
The capsules are lactose free and can be taken in people with lactose intolerance.
The drug is generally well tolerated although side effects may include diarrhea, abdominal distension, nausea and vomiting have been reported for this drug.
The symptom of 'dyspnoea' or feeling of breathlessness can occur although this may settle with repeated doses.
Lubiprostone is shouldn't be taken in bowel obstruction and in those known to be allergic to the drug.
It should be used with caution in pregnancy and the dose lowered in anyone suffering from liver disease.
This drug is an exciting new addition in the treatment of constipation-predominant Irritable Bowel Syndrome.
Because it is still relatively new, it has to be taken with caution and is currently not available in the UK.
The prostone group has potential though and I expect that the drug, or an evolution of it, will become available in due course.
1) Safety and patient outcomes with lubiprostone for up to 52 weeks in patients with irritable bowel syndrome with constipation. Chey WD et al. Aliment Pharmacol Ther. 2012 Mar;35(5):587-99.
2) Efficacy and safety of oral lubiprostone in constipated patients with or without irritable bowel syndrome: a randomized, placebo-controlled and dose-finding study. Fukudo Set al. Neurogastroenterol Motil. 2011 Jun;23(6):544-e205.
3) Clinical trial: lubiprostone in patients with constipation-associated irritable bowel syndrome-results of two randomized, placebo-controlled studies. Drossman DA et al. Aliment Pharmacol Ther. 2009 Feb 1;29(3):329-41.