Safety evaluation of lubiprostone in the treatment of constipation and irritable bowel syndrome

Introduction: Lubiprostone is approved in the United States for the treatment of chronic idiopathic constipation and constipation predominant irritable bowel syndrome (IBS-C). Lubiprostone causes secretion of fluid and electrolytes in the small bowel, through the activation of chloride channels, and thereby induces laxation and improvement of bowel functions. It is generally considered to be safe and effective. Common side effects of lubiprostone include nausea, diarrhea, abdominal pain and bloating, and the rare side effect dyspnea. Likely mechanisms for these side effects may be related to lubiprostone's primary action on small bowel secretion and the associated intestinal distension, as well as smooth muscle contraction. Areas covered: This article reviews the pharmacokinetic and safety profile of lubiprostone, with particular relevance to the two FDA-approved dosages. Expert opinion: Lubiprostone acts topically in the gut lumen and is almost completely metabolized in the gut lumen. Lubiprostone's M3 metabolite can be detected in low concentrations in the serum and may be responsible for some of its side effects. However, the exact mechanisms by which the side effects are produced are currently unknown.