What are the potential side effects of Vimpat (lacosamide) in a patient with a history of epilepsy or seizures?

Vimpat (Lacosamide) Side Effects

Lacosamide is generally well tolerated with most adverse events being mild to moderate in severity, but clinicians must monitor for cardiac conduction abnormalities (PR interval prolongation) and common CNS/gastrointestinal side effects. 1

Most Common Side Effects

The very common adverse reactions that occur with adjunctive lacosamide therapy include 1:

• Diplopia (double vision) - one of the most frequently reported visual disturbances 1
• Dizziness - a common CNS side effect that may affect daily activities 1
• Headache - frequently reported but typically mild to moderate 1
• Nausea - the primary gastrointestinal complaint 1

These adverse events are predominantly mild or moderate in severity and rarely require discontinuation 1.

Critical Cardiac Monitoring Requirements

Small dose-related increases in PR interval occur with lacosamide, requiring caution in patients with pre-existing cardiac conduction abnormalities. 2

• The Mayo Clinic specifically recommends monitoring for PR interval prolongation due to lacosamide's effect on cardiac conduction time 2
• Exercise particular caution in patients with known conduction problems, heart block, or those taking other medications that prolong PR interval 2
• Obtain baseline ECG before initiating therapy in high-risk patients 2

Intravenous Administration-Specific Side Effects

When lacosamide is given intravenously, additional local adverse events may occur 1:

• Injection site discomfort or pain 1
• Injection site irritation 1
• Injection site erythema 1

The tolerability profile of IV lacosamide otherwise remains consistent with oral administration, and both formulations are bioequivalent without requiring dose adjustment when switching 2.

Pediatric Population Side Effects

In critically ill children receiving IV lacosamide for acute repetitive seizures or status epilepticus 3:

• Bradycardia occurred in 23.9% of patients - this is a significant concern requiring cardiac monitoring 3
• Rash developed in 1.5% of patients 3
• The medication demonstrated acceptable safety even in young infants and children under 4 years old 3

Comparative Safety Profile

Lacosamide offers advantages over older antiepileptic drugs due to minimal drug-drug interactions and reduced side effect burden. 4

• The European Society for Medical Oncology recommends lacosamide over enzyme-inducing agents (phenytoin, carbamazepine, phenobarbital) specifically because it avoids interactions with steroids and cytotoxic agents 2
• Physicians may consider levetiracetam or lacosamide over older AEDs to reduce side effects 4
• Unlike older AEDs, lacosamide does not cause the cognitive impairment, neuropsychiatric disorders, myelosuppression, or significant liver dysfunction commonly seen with traditional agents 4

Critical Safety Warnings

Abrupt discontinuation of lacosamide must be avoided as withdrawal seizures can occur with sudden cessation. 2

• Always taper lacosamide gradually when discontinuing 2
• Never stop abruptly, even if side effects develop - manage side effects while maintaining therapy or transitioning to alternative agents 2

Clinical Context for Side Effect Management

The side effect profile of lacosamide is generally more favorable than traditional AEDs, which commonly cause cognitive impairment, neuropsychiatric disorders, fatigue, myelosuppression, liver dysfunction, dermatologic reactions, and significant drug interactions 4. This makes lacosamide particularly valuable in patients requiring polypharmacy or those with brain tumors receiving concurrent chemotherapy 2.