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# 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

- Class: [Antiseizure medicines](https://durgical.com/en/pharmacology/classes/antiseizure-medicines/)
- Ion channel: Voltage-gated sodium channel (Nav)
- ATC code: N03AX18

⇅**Voltage-gated sodium channel (Nav)**Lacosamide

ⓘ 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](https://www.rcsb.org/structure/8S9B) · Drag to rotate · pinch to zoom

## 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.

- Binds voltage-gated sodium channels
- Enhances slow inactivation of the channel
- Hyperexcitable membranes become stable
- 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 →](https://durgical.com/en/conditions/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

### Serious (rare, important)

- PR prolongation, atrioventricular block and ventricular tachyarrhythmias
- Atrial fibrillation or flutter
- Syncope
- Suicidal thoughts
- DRESS (multi-organ hypersensitivity)

## 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.

## Memory aid

Lacosamide: «Lazy-amide» – it makes sodium channels slow to recover (slow inactivation) and the PR interval slow too.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/lacosamide/)

## Related drugs

- [Carbamazepine](https://durgical.com/en/pharmacology/carbamazepine/)
- [Lamotrigine](https://durgical.com/en/pharmacology/lamotrigine/)

## Related conditions

- [Epilepsy and seizures](https://durgical.com/en/conditions/epilepsy-and-seizures/)

[← Back to the class: Antiseizure medicines](https://durgical.com/en/pharmacology/classes/antiseizure-medicines/)

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](https://medlineplus.gov/druginfo/meds/a609028.html) (MedlinePlus (U.S. National Library of Medicine), 2024); [DailyMed - LACOSAMIDE tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f4ffa3ad-1278-4772-9ef8-ed6fdaa47605) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N03AX18) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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