Clozapine-Related Functional Bowel Obstruction: A Rare Adverse Effect Unmasking Quetiapine and Benztropine Interaction Raising Need for Bowel Surveillance

Abstract

Randomized controlled trials demonstrate a significant decline in hospital admissions and length of stay following the initiation of clozapine in individuals with bipolar disorder and schizophrenia, along with an increase in quality-adjusted life years. The morbidity and mortality associated with clozapine-induced gastrointestinal hypomotility (CIGH) is greater than agranulocytosis. Despite this, we only have clozapine risk evaluation and mitigation strategies by the US Food and Drug Administration for white cell count monitoring, but none exists for CIGH. Our case highlights CIGH due to multiple factors and recommendations to prevent it and enhance clozapine compliance by conducting a thorough literature review.

Keywords: CIGH; Clozapine; bowel surveillance; ileus.

Figure 1.

(A and B) Computed tomography of the abdomen and pelvis without contrast shows a huge rectal stool burden representative of constipation with possible impaction. There are upstream small bowel loops with diffuse heterogeneous mucosal wall thickening consistent with enteritis with possible developing colonic obstruction. (C) X-ray of the abdomen supine shows scattered air and stool-filled mildly dilated small and large bowel loops seen throughout the abdomen suspicious for ileus.