Clozapine-Induced Toxic Megacolon: A Rare but Serious Complication

Clozapine is a highly effective antipsychotic medication used for treatment-resistant schizophrenia and schizoaffective disorder, with its use most notably associated with the risk of agranulocytosis. As a result, patients on clozapine are routinely screened and monitored for agranulocytosis, but toxic megacolon--a rare and life-threatening gastrointestinal complication--remains an under-recognized adverse effect. We report the case of a 29-year-old female psychiatric hospital resident with a history of schizoaffective disorder who developed a toxic megacolon while on clozapine therapy. The patient presented with 24 hours of delirium, altered mental status, and a distended, painful abdomen. Despite stabilization efforts, her condition rapidly deteriorated. Emergent decompressive laparotomy revealed a massively dilated colon with solid stool. Postoperatively, she developed abdominal compartment syndrome and underwent a total colectomy for colonic necrosis. Multiple organ failures, including small bowel obstruction, pulmonary emboli, and septic shock, further complicated her clinical course. Despite maximal ICU-level care, she did not survive her condition. This case highlights the need for heightened vigilance and prompt intervention in managing gastrointestinal complications associated with clozapine therapy.