Olanzapine-induced ischemic colitis

Area of Science:

• Gastroenterology
• Pharmacology
• Psychiatry

Background:

• Ischemic colitis (IC) is an uncommon adverse event associated with antipsychotic agents, particularly phenothiazines and atypical neuroleptics.
• The risk of IC is elevated when anticholinergic drugs are co-administered.

Observation:

• A case report details a 38-year-old woman with schizoaffective disorder on chronic quetiapine and recently added olanzapine, who presented with severe diarrhea.
• Physical examination revealed abdominal distension and tenderness, with laboratory tests showing increased acute phase reactants.
• Imaging and colonoscopy confirmed severe ischemic colitis involving multiple colonic segments.

Findings:

• Biopsies confirmed ischemic colitis, strongly suspected to be an adverse effect of olanzapine due to its anticholinergic properties.
• Withdrawal of olanzapine resulted in complete clinical, laboratory, and endoscopic recovery over a 6-month follow-up period.

Implications:

• Antipsychotic medications, including atypical agents like clozapine and olanzapine, should be considered potential causes of ischemic colitis.
• While uncommon, IC associated with antipsychotics can lead to significant morbidity and mortality, necessitating prompt diagnosis and management.
• This case highlights the importance of considering drug-induced adverse effects in the differential diagnosis of colitis, especially in patients with complex medication regimens.