Ischemic Colitis Secondary to Olanzapine and Clonidine Use in a Patient With a History of Laxative Abuse.

Ischemic colitis is the most common type of intestinal ischemia and is caused by an acute arterial occlusion, thrombosis, or hypoperfusion of the mesenteric vasculature. This case centers around a 39-year-old female with a past medical history significant for a 20-year history of stimulant laxative abuse, chronic constipation, bipolar disorder, and anxiety that presented with ischemic colitis following 21 days of obstipation. At the time of presentation, the patient was taking olanzapine 15 mg daily for the treatment of bipolar disorder and clonidine 0.2 mg three times daily for anxiety. Over the course of her hospitalization, the patient was found to have a high stool burden, including calcified stool, contributing to ischemic colitis. She was successfully treated with a clonidine taper, multiple enemas, and laxatives. Pharmacological agents that induce constipation have been shown to increase the risk of colonic ischemia by increasing intraluminal pressure in the colon. Atypical antipsychotics block peripheral anticholinergic and anti-serotonergic receptors, limit gastrointestinal muscle contractions, and delay intestinal transit.