Apparent seizure and atrial fibrillation associated with paliperidone

A case of apparent seizure and atrial fibrillation associated with paliperidone is reported.

A 46-year-old man arrived at the emergency room (ER) via ambulance. Earlier that morning, his wife observed him awakening in a panic, drifting back to sleep, and then subsequently awakening in a panic with an apparent seizure lasting one to two minutes. The episode included tongue biting and urinary incontinence. His medical history included bipolar disorder, diabetes mellitus, hyperlipidemia, and hypertension. The patient's medications included metformin, insulin glargine, insulin lispro, simvastatin, enalapril, escitalopram, lamotrigine, and clonazepam and had not changed for many months except for the recent addition of paliperidone four days before his arrival at the ER. Electrocardiography revealed atrial fibrillation, a ventricular rate of 151 beats/min, a Q-Tc interval of 461 msec, and no significant changes in the ST segment or T wave. He had no chest pain, and all other laboratory test results and vital signs were normal. The patient was admitted for evaluation and given a single oral dose of potassium chloride. Diltiazem i.v. was administered with resultant conversion to normal sinus rhythm, after which the patient's heart rate and Q-Tc interval normalized. The patient was discharged after one day.

A man taking paliperidone and multiple other drugs experienced atrial fibrillation and a possible seizure. Although these are known adverse effects of atypical antipsychotics, it is unusual to have both events occur concurrently and with low-to-average dosages, and these events have not been associated with paliperidone in published case reports.