Torsades de pointes after administration of low-dose aripiprazole

To describe a case of torsades de pointes (TdP) in a patient treated with aripiprazole.

A 42-year-old white male with schizophrenia, diabetes, hypertension, and a history of stroke was admitted to the intensive care unit following 2 days of fever, diarrhea, and altered mental status. Following the resolution of his acute illness, previous therapy with quetiapine 400 mg orally at bedtime was resumed for schizophrenia and presumed delirium. Quetiapine was discontinued after 1 dose because of QTc interval prolongation. Twenty-three days later, with a baseline QTc interval of 414 milliseconds, aripiprazole 2.5 mg orally once daily was initiated. Following 5 days of aripiprazole therapy, the patient had a cardiac arrest due to TdP. Normal sinus rhythm was restored after 30 seconds of cardiopulmonary resuscitation, 1 shock of 200 Joules, and 4 g of intravenous magnesium sulfate. Serial electrocardiographs obtained after aripiprazole discontinuation revealed resolution of QTc interval prolongation.

Aripiprazole is a second-generation antipsychotic that may be selected for patients with prolonged QTc intervals and at risk for TdP. Data from trials indicate that aripiprazole has minimal effects on the QTc interval. However, in this case, aripiprazole was associated with TdP in a patient with minimal risk factors. The Naranjo probability scale was used to determine a probable association between aripiprazole and the development of TdP. To our knowledge, this is the first reported case of TdP associated with the use of aripiprazole.

Five days of low-dose aripiprazole therapy was associated with the development of TdP in a man with minimal risk factors. Clinicians should be aware of this potential adverse drug event with aripiprazole.