Acute Valproic Acid Overdose Leading to AV Conduction Block: A Case Report

Patients with acute valproic acid toxicity with overdose usually present with hypotension, respiratory depression, and tachycardia. 1 Bradycardia has been reported in a case report associated with acute valproic acid toxicity. 2 Atrioventricular conduction block has been reported once before as a rare complication of valproic acid use present at therapeutic levels. 3 However, valproic acid overdose has never been reported to be associated with symptomatic bradycardia with AV conduction block requiring intervention. Here we present, for the first time, a case of acute valproic acid overdose leading to symptomatic bradycardia with AV nodal conduction block requiring intervention. In patients with persistent hypotension and bradycardia with appropriate risk factors, valproate overdose should be considered as a potential etiology. Before considering pacemaker implantation in such patients, valproic acid levels should be investigated and discontinued. For management of bradycardia and AV nodal conduction abnormality in acute valproic acid ingestion, symptomatic treatment of hypotension and bradycardia with atropine is of utmost importance for hemodynamic stability. Secondly, patients with confirmed valproate overdose via delayed-release formulations should be carefully monitored on telemetry for the development of symptomatic bradycardia and AV nodal block with multiple valproic acid levels to determine peak with prolonged observation if showing any signs including lethargy or somnolence. 7 Lastly, disposition of these patients is likely going to be toward the Intensive Care Unit (ICU), and then subsequently appropriate psychiatric care.