Müller‐Lissner, S.

Constipation is a common problem, affects 15% of the population, and is often self-diagnosed and self-managed. Over the past 3 decades, there have been significant advances in our understanding and management of chronic constipation, with the emerging recognition that occasional constipation (OC) is another subtype that falls outside current classifications. The purpose of this review was to describe the process of developing and proposing a new definition for OC based on expert consensus and taking into consideration the multifactorial nature of the problem such as alterations in bowel habit that include stool frequency and difficulty with stool passage, perception of the sufferer, duration of symptoms, and potential responsiveness to treatment. Leading gastroenterologists from 5 countries met virtually on multiple occasions through an online digital platform to discuss the problem of OC and recommended a practical, user-friendly definition: “OC can be defined as intermittent or occasional symptomatic alteration(s) in bowel habit. This includes a bothersome reduction in the frequency of bowel movements and/or difficulty with passage of stools but without alarming features. Bowel symptoms may last for a few days or a few weeks, and episodes may require modification of lifestyle, dietary habits and/or use of over-the-counter laxatives or bulking agents to restore a satisfactory bowel habit.” Prospective studies are required to validate this definition and determine OC prevalence in the community. This review highlights current knowledge gaps and could provide impetus for future research to facilitate an improved understanding of OC and development of evidence-based management guidelines.

Summary Background The nonselective 5‐ HT 4 receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events ( AEs ). Aim To perform a systematic review of the safety profile, particularly cardiovascular, of 5‐ HT 4 agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy. Methods Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD ‐5108 (velusetrag) and ATI ‐7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006–2008 and DDW 2008–2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data. Results Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5‐ HT 4 agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5‐ HT 4 agonists had reports of cardiovascular AEs : cisapride ( QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5‐ HT 1 receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5‐ HT 4 agonists prucalopride, velusetrag, naronapride, or for nonselective 5‐HT 4 agonists with no hERG or 5‐ HT 1 affinity (renzapride, clebopride, mosapride). Conclusions 5‐ HT 4 agonists for GI disorders differ in chemical structure and selectivity for 5‐ HT 4 receptors. Selectivity for 5‐ HT 4 over non‐5‐ HT 4 receptors may influence the agent's safety and overall risk–benefit profile. Based on available evidence, highly selective 5‐ HT 4 agonists may offer improved safety to treat patients with impaired GI motility.