A case of donepezil-related torsades de pointes

An 80-year-old woman with Alzheimer's dementia presented with diarrhoea, vomiting and worsening confusion following an increase in donepezil dose from 5 to 10 mg. The ECG revealed prolongation of QTc interval. Soon after admission, she became unresponsive with polymorphic ventricular tachycardia (VT). Cardiopulmonary resuscitation with a 200 J shock was successful in establishing cardiac output. Following the discontinuation of donepezil, the QTc interval normalized and no further arrhythmias were recorded. Treatment with anticholinesterase inhibitors may result in lifethreatening VT. Vigilance is required for the identification of this condition in patients presenting with presyncope, syncope or seizures.