Clozapine-induced Gastrointestinal Hypomotility--New Objective Evidence for an Underestimated Side-effect.

Available online 27 February 2016 serum levels and (3) that this hypomotilitywas not reported by patients by themeans of subjective constipation symptoms. Remarkably, CTTs in clozapine were four times longer than for other antipsychotics or population norms and 4 of 5 clozapine-treated patients showed clear Clozapine is still the most effective antipsychotic drug in the manhypomotility (Every-Palmer et al., 2016). Therefore, the work of agement of treatment-resistant schizophrenia and alternative strategies are currently not foreseeable. Clinicians are aware of the typical and frequent clozapine side-effects such as hypotension, sedation, tachycardia and sialorrhea aswell as the rare but nevertheless life-threatening complications like agranulocytosis or myocarditis. However, clozapineinduced constipation with the consecutive risk for ileus still receives little attention, which is a matter of concern: (1) constipation linked to antipsychotic treatment is generally underestimated (De Hert et al., 2011a) and (2) clozapine seems to be specifically associated with high-grade constipation, intestinal obstruction and paralytic ileus (De Fazio et al., 2015; Palmer et al., 2008; DeHert et al., 2011b). International guidelines address antipsychotic-induced constipation (Hasan et al., 2012) and provide evidence-based pharmacological and nonpharmacological treatment recommendations based on a sparse database (Hasan et al., 2013). To fill the clinician's knowledge gap, new evidence regarding antipsychotic-induced constipation and the relationship to certain compounds is needed. Every-Palmer et al. (2016) provide a novel and important study to shed more light on this relationship. They used for the very first time a standardized radiopaquemarker method (multiple radiopaquemarker (ROM) bolus technique) to measure colonic transit times (CTTs) of patients receiving antipsychotics aswell as comparing the effects of clozapine and non-clozapine antipsychotic agents on CCT. This approach is new for clinical psychiatry and allows for a reliable and objective measure of CCT with limited burden for the patients. Their work is of particular significance, as it (1) reveals for the first time increased CTTs in nearly all patients receiving clozapine (but surprisingly not in nonclozapine treated patients), (2) that this is associatedwith the clozapine