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Pharmacology · Antiseizure medicines

Lacosamide !

A sodium channel antiseizure medicine that enhances slow inactivation. It can lengthen the PR interval of the ECG and is given by mouth or vein.

Updated 2026-11-01

The figure shows lacosamide bound to human Nav1.7 (SCN9A), a peripheral sodium channel of the same family as the brain channels it acts on in epilepsy.

Target in 3D: Voltage-gated sodium channel (Nav). PDB structure 8S9B (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Lacosamide selectively enhances the slow inactivation of voltage-gated sodium channels. This differs from older sodium channel blockers, which act on fast inactivation. Hyperexcitable membranes are stabilized and repetitive firing is inhibited.

  1. Binds voltage-gated sodium channels
  2. Enhances slow inactivation of the channel
  3. Hyperexcitable membranes become stable
  4. Repetitive firing of the seizure focus is inhibited

Pharmacokinetics

Absorption
Absorbed by mouth; peak about 1 to 4 hours after an oral dose
Elimination
Kidneys; the dose is adjusted in severe kidney or liver disease
Half-life
About 13 hours, the same orally and intravenously

Indications

  • Focal (partial-onset) seizures, alone or as add-on Epilepsy and seizures →
  • Intravenous use when the oral route is temporarily not possible

Adverse effects

Common

  • Double vision
  • Dizziness and unsteadiness (ataxia)
  • Headache
  • Nausea
  • Sleepiness

Contraindications

  • None listed in the label; used with great caution in conduction disorders or severe heart disease

Key interactions

Other drugs that affect cardiac conduction (sodium channel blockers, beta-blockers, calcium channel blockers, potassium channel blockers)
Further PR prolongation and conduction block
Strong CYP3A4 or CYP2C9 inhibitors in kidney or liver impairment
Higher lacosamide levels

What is monitored

  • ECG before and after starting in people with heart disease or on conduction-slowing drugs
  • Dizziness, falls and vision
  • Kidney and liver function
  • Mood and suicidal thoughts

Administration and safety

  • Given by mouth or intravenously; oral and intravenous doses are equivalent
  • Controlled medicine in some countries
  • Withdrawn gradually: stopping suddenly can trigger seizures

Nursing care

  • Check pulse and ECG when indicated, and ask about palpitations or fainting
  • Warn about dizziness and double vision before driving
  • Teach to report rash or fever
  • Teach not to stop suddenly

Pregnancy and breastfeeding

Human data are limited; benefits and risks are weighed with specialist care.

Test yourself

Think of the answer, then tap the question to see it.

How does lacosamide differ from carbamazepine at the sodium channel?

Lacosamide enhances slow inactivation of the channel; carbamazepine and phenytoin act mainly on fast inactivation.

Which ECG change is typical of lacosamide?

PR interval prolongation, which can progress to atrioventricular block, especially with other conduction-slowing drugs.

Can lacosamide be given intravenously?

Yes. The intravenous form replaces oral doses when the oral route is temporarily not possible.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: Lacosamide: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2024); DailyMed - LACOSAMIDE tablet, film coated (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.