What is lacosamide used for?: Understanding This Anti-Seizure Medication

October 7, 2025 •

4 min read

Originally approved by the FDA in 2008, lacosamide, known by the brand name Vimpat, is a modern anti-seizure medication that functions differently from older drugs. A key question for many patients and caregivers is: What is lacosamide used for? It is primarily prescribed to control specific types of seizures associated with epilepsy.

Quick Summary

Lacosamide is an anti-epileptic drug (AED) used for treating focal-onset and primary generalized tonic-clonic seizures. It works by affecting the slow inactivation of sodium channels in the brain, helping to stabilize overactive neuronal membranes and reduce seizure frequency. Available in multiple formulations, it can be used as a standalone or adjunctive therapy for adults and children with epilepsy.

Key Points

Primary Use: Lacosamide is used to treat focal-onset seizures and, as an add-on therapy, primary generalized tonic-clonic seizures in adults and children.
Unique Mechanism: It works by selectively enhancing the slow inactivation of voltage-gated sodium channels, which helps stabilize nerve cells and reduce repetitive firing.
Flexible Formulations: The drug is available as oral tablets, a liquid solution, and an intravenous injection, allowing for flexibility in administration.
Potential Side Effects: Common side effects include dizziness, headache, nausea, and double vision. Serious side effects can include heart rhythm problems and mood changes.
Controlled Substance: Due to a low potential for abuse and dependence, lacosamide is classified as a Schedule V controlled substance.
Favorable Cognitive Profile: Studies suggest that lacosamide may have a better cognitive profile than some other anti-seizure medications, such as carbamazepine.

Lacosamide is a prescription medication in the class of drugs known as anticonvulsants or anti-epileptic drugs (AEDs). It is approved for use in both adults and children, serving as a critical tool in managing certain types of epilepsy. The specific applications for this drug depend on the type of seizure and the patient's age.

What is lacosamide used for?

Lacosamide is specifically indicated for the treatment of seizures associated with epilepsy. Its uses include:

Focal-Onset Seizures: This is the primary indication for lacosamide. Focal-onset (or partial-onset) seizures begin in a specific area of the brain. Lacosamide can be used as monotherapy (alone) or as adjunctive therapy (in combination with other AEDs) for patients with this type of seizure. It is approved for use in patients as young as one month of age.
Primary Generalized Tonic-Clonic Seizures: For this type of seizure, often referred to as a "grand mal seizure," lacosamide is used as an adjunctive treatment. This means it is taken alongside other medications to help control seizures that affect the entire body from the outset. It is approved for this use in patients aged four years and older.
Status Epilepticus: Although not a primary, routine use, some studies have explored lacosamide as an alternative treatment for status epilepticus (a medical emergency where seizures are prolonged or occur in clusters) when other treatments like levetiracetam or valproate are ineffective or not suitable.

Understanding the Mechanism of Action

Unlike older AEDs that target sodium channels by blocking their fast inactivation, lacosamide has a more selective and specific mechanism. Its action involves the selective enhancement of the slow inactivation of voltage-gated sodium channels.

This targeted approach offers several benefits:

Stabilizes Neuronal Membranes: By enhancing slow inactivation, lacosamide stabilizes hyperexcitable neuronal membranes, which are a hallmark of epileptic activity.
Inhibits Repetitive Firing: It inhibits the repetitive firing of nerves, reducing the excessive electrical activity in the brain that causes seizures.
Minimizes Side Effects: Because it does not interfere with the fast inactivation process crucial for normal brain function, this selective action helps to minimize some of the cognitive side effects associated with less-selective AEDs.

Lacosamide also has another proposed, though less understood, mechanism involving its interaction with collapsin-response mediator protein 2 (CRMP-2), a protein implicated in both epilepsy and neuropathic pain.

Administration

Lacosamide is available in several formulations to suit patient needs.

Oral Formulations: These include tablets and a liquid solution taken by mouth, typically twice a day.
Intravenous (IV) Injection: This formulation is used in hospital settings for patients who are temporarily unable to take oral medication.

The administration schedule is determined by a healthcare provider based on the patient's age, weight, and seizure type.

Common Side Effects and Warnings

Like all medications, lacosamide can cause side effects. Common ones often decrease over time as the body adjusts.

Common Side Effects

Dizziness or feeling lightheaded
Headache
Nausea or vomiting
Blurred or double vision (diplopia)
Drowsiness or fatigue
Coordination problems or unsteadiness

Serious Warnings and Side Effects

Heart Rhythm Changes: Lacosamide can affect heart rhythm, potentially causing a fast or irregular heartbeat. Patients with pre-existing heart conditions should be monitored carefully.
Suicidal Thoughts or Behavior: Like many anti-seizure medications, lacosamide may increase the risk of suicidal ideation or depression. Mood changes should be reported immediately.
Severe Skin Reactions: A rare but serious side effect is a drug reaction with eosinophilia and systemic symptoms (DRESS), which can involve fever, rash, and swollen lymph nodes.
Controlled Substance Status: Lacosamide is a Schedule V controlled substance due to the potential for abuse and dependence, although the risk is low. It should be stored securely.

Lacosamide vs. Other Anti-Seizure Medications

Lacosamide's unique mechanism sets it apart from other common AEDs. The following table provides a comparison with two other widely used anti-seizure drugs, levetiracetam (Keppra) and carbamazepine (Tegretol).


Feature	Lacosamide (Vimpat)	Levetiracetam (Keppra)	Carbamazepine (Tegretol)
Mechanism	Enhances slow inactivation of voltage-gated sodium channels.	Binds to the synaptic vesicle protein 2A (SV2A), modulating neurotransmitter release.	Blocks repetitive firing of voltage-gated sodium channels.
Indications	Focal-onset seizures (monotherapy/adjunctive), Primary Generalized Tonic-Clonic seizures (adjunctive).	Broad spectrum, including focal, myoclonic, and primary generalized tonic-clonic seizures.	Focal-onset seizures, trigeminal neuralgia.
Common Side Effects	Dizziness, headache, nausea, diplopia.	Irritability, sleepiness, mood changes.	Dizziness, drowsiness, nausea, rash.
Cognitive Impact	Generally considered to have a favorable cognitive profile.	May cause mood or behavioral side effects.	Can cause cognitive impairment, especially at higher levels.
Drug Interactions	Minimal, as it's not a strong inducer or inhibitor of CYP enzymes.	Minimal interactions.	Significant interactions, as it is a strong inducer of CYP enzymes.

Conclusion

Lacosamide is a valuable and often well-tolerated anti-epileptic medication, primarily used for controlling focal-onset seizures and, in combination with other drugs, primary generalized tonic-clonic seizures. Its distinct mechanism of selectively enhancing the slow inactivation of sodium channels offers effective seizure control with a potentially more favorable cognitive side effect profile compared to some older drugs. For individuals considering or using this medication, it is essential to have a comprehensive discussion with a healthcare provider to understand its benefits, risks, and proper usage in the context of their specific epilepsy management plan. For further information and support, the Epilepsy Foundation website is an excellent resource.

Frequently Asked Questions

The most common brand name for lacosamide is Vimpat, though it may also be available under other brand names, such as Motpoly XR.

Yes, lacosamide can be used as a monotherapy (by itself) for the treatment of focal-onset seizures in adults and children aged four years and older.

Yes, lacosamide is classified as a Schedule V controlled substance in the United States, indicating that it has a potential for abuse or dependence, though lower than drugs in other schedules.

Lacosamide is typically taken twice a day, approximately 12 hours apart. The specific schedule will be determined by a healthcare provider.

You should contact your healthcare provider if you experience side effects. For serious side effects like heart palpitations or mood changes, seek immediate medical attention.

Lacosamide's key difference is its mechanism of action, which involves selectively enhancing the slow inactivation of sodium channels rather than broadly blocking them. This specific action may result in fewer cognitive side effects.

Lacosamide is FDA-approved for specific types of seizures in children as young as one month for focal-onset seizures and four years for primary generalized tonic-clonic seizures. The administration is carefully determined based on body weight and other factors.