What are the side effects of Lacosamide (Vimpat)?

Lacosamide Side Effects

Lacosamide is generally well tolerated with the most common side effects being dizziness, headache, nausea, diplopia (double vision), and drowsiness, though cardiovascular effects including PR interval prolongation require monitoring. 1, 2, 3

Most Common Neurological Side Effects

The following adverse effects occur most frequently and are typically mild to moderate in severity:

• Dizziness is the most commonly reported treatment-related adverse event, occurring significantly more often than placebo (RR 3.53) 3, 4, 5
• Headache occurs frequently, though not always at statistically significant rates compared to placebo 1, 3, 6
• Diplopia (double vision) is significantly associated with lacosamide treatment (RR 5.29) 1, 3
• Drowsiness and somnolence are reported but may not reach statistical significance in all studies 1, 2, 3
• Abnormal coordination/ataxia shows a strong association with lacosamide (RR 6.12) 1, 3

Gastrointestinal Side Effects

• Nausea is significantly more common with lacosamide than placebo (RR 2.37) 3, 5, 6
• Vomiting occurs with increased frequency (RR 3.49) 1, 3
• Abdominal pain has been reported in clinical trials 1

Cardiovascular Effects

• Small dose-related increases in PR interval have been observed and require monitoring 7
• Heart damage and cardiovascular abnormalities have been reported, though less commonly 2

Rare but Serious Adverse Effects

While uncommon, the following warrant clinical attention:

• Skin rashes have been documented 2
• Hematotoxicity (blood-related toxicity) has been reported 2
• Psychological symptoms and suicide risk require monitoring 2

Driving and Safety Considerations

• Lacosamide may impair driving ability due to central nervous system effects, particularly during treatment initiation or dose changes 1, 7
• Patients must be counseled about potential driving impairment; failure to warn patients represents a significant clinical pitfall that could lead to accidents 7
• The incidence of arousal-related adverse events with lacosamide was lower than that for carbamazepine, and epidemiological studies show no increased risk of traffic accidents compared to other antiepileptic drugs 1

Dose-Related Patterns

• Higher doses (400-600 mg/day) are more associated with adverse effects and drug withdrawal than lower doses (200 mg/day) 3
• Most treatment-emergent adverse events are mild or moderate in severity across all dose ranges 1, 4

Intravenous Formulation Safety

• When lacosamide is administered intravenously (15-, 30-, or 60-minute infusions), the safety and tolerability profile is comparable to oral administration 1, 4, 5
• Reported adverse effects with IV administration include dizziness, headache, back pain, somnolence, and injection site pain, all considered mild or moderate 1

Critical Clinical Pitfall

• Abrupt discontinuation of lacosamide may precipitate seizures, which poses greater risk than continuing the medication even in special populations like pregnancy 7, 8