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

Area of Science:

• Pharmacology
• Cardiology
• Neurology

Background:

• Lacosamide is a newer antiepileptic drug known to potentially prolong the PR interval.
• Drug interactions and cardiac effects, particularly in the elderly, require careful consideration.

Observation:

• An 88-year-old woman with epilepsy and neurodegenerative disease was initiated on lacosamide.
• The patient was also concurrently treated with bisoprolol for other medical conditions.

Findings:

• The patient developed a complete third-degree atrioventricular block shortly after starting lacosamide.
• This cardiac event necessitated pacemaker implantation.
• The atrioventricular block was not clearly dose-dependent, suggesting a drug-drug interaction as a potential cause, particularly with bisoprolol.

Implications:

• This case underscores the importance of monitoring cardiac conduction in elderly patients initiating lacosamide, especially when co-prescribed with other PR interval-extending drugs like bisoprolol.
• Physicians should exercise caution regarding potential drug-drug interactions between lacosamide and beta-blockers.
• Further investigation into the interaction between lacosamide and bisoprolol regarding atrioventricular conduction is warranted.