What are the potential side effects of Lacosamide (Vimpat)?

Lacosamide Side Effects

The most common side effects of lacosamide (Vimpat) include dizziness, headache, nausea, somnolence, diplopia (double vision), and injection site pain when administered intravenously. 1, 2

Common Side Effects

Lacosamide is generally well-tolerated, with most adverse events being mild to moderate in severity:

• Central Nervous System effects:

  • Dizziness (most common)
  • Headache
  • Drowsiness/somnolence
  • Vertigo
  • Ataxia (impaired coordination)

• Visual disturbances:

  • Diplopia (double vision)

• Gastrointestinal effects:

  • Nausea
  • Vomiting

• Administration-related:

  • Injection site pain (with IV formulation)

Cardiovascular Side Effects

Lacosamide has dose-dependent effects on cardiac conduction that require special attention:

• PR interval prolongation (dose-related)
• Risk of atrioventricular (AV) block, particularly in:
  • Elderly patients
  • Patients with pre-existing cardiac conduction disorders
  • Patients taking other medications that affect cardiac conduction
  • Patients with renal impairment 3

Rare but Serious Side Effects

Several less common but potentially serious adverse effects have been reported:

• Skin reactions: Rashes have been reported, though less frequently than with other antiseizure medications 4

• Hematologic effects: Rare cases of hematotoxicity 4

• Psychiatric symptoms:

  • Depression
  • Anxiety
  • Irritability
  • Suicidal ideation (requires monitoring) 4

Overdose Effects

In cases of significant overdose, the following have been observed:

• Coma
• Seizures (paradoxically)
• Hypotension
• Prolonged PR interval
• Complete AV block (in extreme cases) 5, 3

Comparison to Other Antiseizure Medications

Lacosamide has some advantages over other antiseizure medications:

• Lower incidence of arousal-related adverse events compared to carbamazepine 1
• Does not induce or inhibit cytochrome P450 enzymes, resulting in fewer drug-drug interactions than older antiseizure medications 2, 6
• Minimal protein binding, reducing potential for drug interactions 7

Monitoring Recommendations

For patients taking lacosamide, the following monitoring is advised:

• Baseline ECG: Particularly in patients with known cardiac conduction problems or taking other medications that affect cardiac conduction
• Periodic cardiac assessment: For patients on long-term therapy or at higher doses
• Mental health monitoring: Watch for signs of depression or suicidal ideation
• Driving ability: Patients should be counseled about potential effects on driving performance, especially during initial titration 1, 2

Special Populations

• Elderly patients: May be more susceptible to side effects, particularly cardiac effects
• Patients with renal impairment: Higher risk of adverse effects, including cardiac conduction abnormalities 3
• Pregnant women: Limited data available; risk-benefit assessment needed

Clinical Pearls

• Side effects are often dose-dependent and may be more pronounced during initial titration
• Starting with lower doses and gradually increasing can help minimize adverse effects
• Most side effects are transient and improve with continued treatment
• The incidence of serious adverse effects is relatively low compared to older antiseizure medications

Lacosamide's unique mechanism of action (selective enhancement of slow inactivation of voltage-gated sodium channels) contributes to its generally favorable side effect profile when used at recommended doses 6, 7.