Lubiprostone

Lubiprostone (rINN, marketed under the trade name Amitiza among others) is a medication used in the management of chronic idiopathic constipation, predominantly irritable bowel syndrome-associated constipation in women and opioid-induced constipation. The drug is owned by Mallinckrodt and is marketed by Takeda Pharmaceutical Company.
The drug was developed by Sucampo Pharmaceuticals and approved by the Food and Drug Administration (FDA) in 2006. It was recommended for use in the UK by the National Institute for Health and Care Excellence (NICE) in July 2014. Health Canada approved the drug in 2015.
The cost to the NHS was £29.68 per 24 mg 28-cap pack as of April 2017.
Lubiprostone received approval from the Food and Drug Administration in 2008 to treat irritable bowel syndrome with constipation (IBS-C) and is available through prescription only.
The drug is available in the United States, Japan, Switzerland, India, United Kingdom; and Canada.
In Bangladesh and India, lubiprostone is marketed under the trade name Lubigut by Ziska Pharmaceuticals, Lubilax by Beacon Pharmaceuticals, and under the trade name Lubowel by Sun Pharmaceutical.
Medical uses.
Lubiprostone is used for the treatment of chronic constipation of unknown cause in adults, as well as irritable bowel syndrome associated with constipation in women.
Lubiprostone is approved to treat chronic idiopathic constipation (CIC) in adults.
Lubiprostone is also approved to treat opioid-induced constipation, in adults with chronic non-cancer pain. The effectiveness of lubiprostone has not been established in patients who are taking a diphenylheptane opioid (e.g., methadone).
Lubiprostone is approved to treat irritable bowel syndrome with constipation (IBS-C) in women 18 years of age and older.
Lubiprostone has not been studied in children. There is current research under way to determine the safety and efficacy in postoperative bowel dysfunction.
Adverse effects.
In clinical trials, the most common adverse event was nausea (31%). Other adverse events (≥5% of patients) included diarrhea (13%), headache (13%), abdominal distension (5%), abdominal pain (5%), flatulence (6%), sinusitis (5%), vomiting (5%), and fecal incontinence (1%).
Contraindications.
There is no current data on use in people with liver or kidney complications. The effects on pregnancy have not been studied in humans but testing in guinea pigs resulted in fetal loss.
Amitiza is not approved for use in children. Lubiprostone is contraindicated in patients exhibiting chronic diarrhea, bowel obstruction, or diarrhea-predominant irritable bowel syndrome.
Mechanism of action.
Lubiprostone is a bicyclic fatty acid derived from prostaglandin E1 that acts by specifically activating ClC-2 chloride channels on the apical aspect of gastrointestinal epithelial cells, producing a chloride-rich fluid secretion. These secretions soften the stool, increase motility, and promote spontaneous bowel movements (SBM).
Symptoms of constipation such as pain and bloating are usually improved within one week, and SBM may occur within one day.
Pharmacokinetics.
Unlike many laxative products, lubiprostone does not show signs of drug tolerance, chemical dependency, or altered serum electrolyte concentration. There was no rebound effect following withdrawal of treatment, but a gradual return to pre-treatment bowel movement frequency should be expected.
Minimal distribution of the drug occurs beyond the immediate gastrointestinal tissues. Lubiprostone is rapidly metabolized by reduction/oxidation, mediated by carbonyl reductase. There is no metabolic involvement of the hepatic cytochrome P450 system. The measurable metabolite, M3, exists in very low levels in plasma and makes up less than 10% of the total administered dose.
Data indicate that metabolism occurs locally in the stomach and jejunum.