Complete Atrioventricular Block in an Elderly Patient Treated with Low-Dose Lacosamide

Lacosamide, one of the last antiepileptic drugs marketed, can cause extension of PR interval. Precautions are recommended when used in elderly and with other drugs extending PR interval. Cases of severe third-degree atrioventricular block have been reported only in post-marketing case reports when used at high-doses and remain rare. We report the case of an 88-year-old woman treated with bisoprolol, who experienced a complete atrioventricular block after initiation of lacosamide for epilepsy associated with neurodegenerative disease. This dramatic event required a pacemaker implementation. Not being dose-dependent (initiation dosage used), it seemed partially explained by drug–drug interaction with bisoprolol.