Delirium Due to Olanzapine and Clonazepam Interaction in a Patient with Mania

Abstract This case report details the clinical course of a 41-year-old male presenting with a manic episode with psychotic features, who had an episode of delirium. He exhibited decreased need for sleep, excessive energy, overfamiliarity, grandiose delusions (believing he was “Lord Krishna”), and a Young Mania Rating Scale (YMRS) score of 40. Initial treatment with olanzapine (20 mg HS) and divalproate (1250 mg daily) reduced the YMRS score to 20 within 3 days. On day 24, oversedation occurred, followed by insomnia, prompting clonazepam (0.5 mg) administration. On day 25, the patient developed disorientation, disorganized behavior (e.g., picking up nonexistent garbage), slurred speech, and agitation, suggestive of delirium. Differential diagnoses include medication toxicity, drug interaction, medical delirium, or worsening psychosis. Management involved holding medications, laboratory tests (e.g., divalproate levels and serum electrolytes), and assessing for neurological causes. This case highlights the need for careful medication management and comprehensive evaluation.