A 53-year-old man is brought to the emergency department after a witnessed seizure 1 hour prior. The patient lives in a group home and was observed by the staff to suddenly become stiff and unresponsive during lunch. He was then noted to have brief jerking movements of his arms and was lowered to the floor. The patient regained consciousness after 1-2 minutes. Medical history includes schizoaffective disorder with multiple hospitalizations for psychotic and mood episodes beginning at age 22. Vital signs are within normal limits. On physical examination, the patient is awake and alert. A 1-cm laceration is noted on the right side of the tongue. Musculoskeletal, cardiopulmonary, and neurologic examinations show no abnormalities. Serum chemistry is normal. A CT scan of the head reveals no abnormalities. Which of the following medications most likely contributed to this patient's presentation?

Question

A 53-year-old man is brought to the emergency department after a witnessed seizure 1 hour prior.  The patient lives in a group home and was observed by the staff to suddenly become stiff and unresponsive during lunch.  He was then noted to have brief jerking movements of his arms and was lowered to the floor.  The patient regained consciousness after 1-2 minutes.  Medical history includes schizoaffective disorder with multiple hospitalizations for psychotic and mood episodes beginning at age 22.  Vital signs are within normal limits.  On physical examination, the patient is awake and alert.  A 1-cm laceration is noted on the right side of the tongue.  Musculoskeletal, cardiopulmonary, and neurologic examinations show no abnormalities.  Serum chemistry is normal.  A CT scan of the head reveals no abnormalities.  Which of the following medications most likely contributed to this patient's presentation?

Quizplus · Accepted Answer

Of the medications listed, the second-generation antipsychotic clozapine has the greatest risk of causing seizures. Clozapine is indicated for treatment-resistant psychosis, and this patient's long history of schizoaffective disorder with multiple hospitalizations and limited functional independence (ie, living in a group home) make it likely that he was prescribed clozapine. Clozapine is the most effective antipsychotic for treatment-resistant schizophrenia and schizoaffective disorder, but its use is limited by several serious adverse effects, including neutropenia/agranulocytosis, seizures, and myocarditis. Compared with other antipsychotics, clozapine carries the greatest risk of seizure. The risk is dose-dependent, although clozapine-induced seizures may occur at any dose level. Tonic-clonic seizures are the most common seizure type observed. (Choice A) Buspirone, a partial serotonin agonist used in the treatment of generalized anxiety disorder, is not associated with an increased risk of seizures. It can cause dizziness and orthostatic hypotension. (Choice B) Carbamazepine, an anticonvulsant that is also used as a mood stabilizer, would not cause seizures. It is associated with gastrointestinal (eg, nausea, vomiting), dermatologic (eg, rash, pruritus), and neurologic (eg, drowsiness, blurred vision) side effects. Toxicity can manifest with cerebellar findings and anticholinergic symptoms. (Choice C) The selective serotonin reuptake inhibitor citalopram is much less likely to cause seizures compared with clozapine. Citalopram is associated with dose-dependent QT prolongation. (Choice E) Phenelzine is a monoamine oxidase inhibitor used in treatment-resistant depression. It has the potential to cause hypertensive crisis and serotonin syndrome due to food and drug interactions but is not associated with a high risk of seizures. Educational objective: The antipsychotic clozapine is associated with an increased risk of seizure. References: Seizure associated with clozapine: incidence, etiology, and management. (http://www.ncbi.nlm.nih.gov/pubmed/25537107) Use of anticonvulsants as prophylaxis for seizures in patients on clozapine. (http://www.ncbi.nlm.nih.gov/pubmed/23996793)

A 53-Year-Old Man Is Brought to the Emergency Department After