lacosamide
Lacosamide (Vimpat) is an antiepileptic. People 1 month and older can take it on its own or with other antiepileptics for partial-onset seizures (also called focal aware seizures). It's also an add-on medication for people 4 years and older who have primary generalized tonic-clonic (PGTC) seizures (or grand mal seizures). Lacosamide (Vimpat) comes as tablets and an oral solution that's taken by mouth twice a day. It's also available as an injection that's used in the hospital. Side effects include dizziness, headache, and nausea. Lacosamide (Vimpat) comes as both brand-name and generic versions, but it's a controlled substance.
What is Lacosamide (Vimpat)?
What is Lacosamide (Vimpat) used for?
Partial-onset seizures (or focal aware seizures) - for people at least 1 month of age
Primary generalized tonic-clonic (PGTC) seizures - for people at least 4 years old
How Lacosamide (Vimpat) works
Lacosamide (Vimpat) is an antiepileptic, which is another name for an anti-seizure medication. It's not exactly clear how the medication works to treat seizures. But researchers think it blocks nerve signaling in the brain. This helps calm your brain activity to control seizures.
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What are the risks and warnings for Lacosamide (Vimpat)?
Lacosamide (Vimpat) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk of suicidal thoughts and behavior
Antiepileptics like lacosamide (Vimpat) can raise the risk of having thoughts about suicide or hurting yourself. Watch for signs of depression and any unusual changes in mood or behavior. This is especially important in the first few months of taking lacosamide (Vimpat) or after a dose change.
Call your care team if you or someone close to you notices anything worrisome. If you start thinking about hurting yourself, call 911 or get medical help right away.
Dizziness and problems with controlling movements
Risk factors: Taking higher doses of lacosamide (Vimpat)
Lacosamide (Vimpat) can make you feel dizzy. It can also make you have problems with movement or coordination. These side effects usually happen when you first start the medication or when you switch to a higher dose. Talk to your prescriber if these side effect don't go away or if it's too bothersome.
Abnormal heartbeat
Risk factors: History of abnormal heartbeat | Heart attack | Heart failure | Structural heart disease | Taking other medications that affect heartbeat or heart rhythm
Lacosamide (Vimpat) can change how your heart beats. It might make your heart beat in an abnormal way. Rarely, this can be life-threatening.
It's important to tell your prescriber and pharmacist about all your health conditions and medications that you take. This helps them check if you're at risk for heartbeat changes. The risk is higher if you already have heart problems. And some other medications can raise this risk if you take them with lacosamide (Vimpat).
If you're at risk, your prescriber will have you get a test done called an electrocardiogram (EKG). This test checks the electrical signals of your heart. You'll need an EKG before you start lacosamide (Vimpat) and regularly while you're taking it.
Get medical help right away if you feel any chest discomfort or palpitations while taking lacosamide (Vimpat). Also get help if you feel like you're going to pass out.
Fainting
Risk factors: Taking high doses of lacosamide (Vimpat) | Taking other medications that affect heartbeat | At risk of heart disease
Although it hasn't happened in people with partial-onset seizures, those who took lacosamide (Vimpat) for some other off-label use fainted during treatment. Most times, this was related to having low blood pressure when getting up too quickly. It's also been related to having an abnormal heartbeat, which might happen while you're taking lacosamide (Vimpat).
To be safe, make sure to get up slowly if you've been sitting or lying down for a while. If you feel like you're going to faint or pass out, try lying down and raising your legs. This helps move your blood to your heart and raise your blood pressure. If that doesn't help, call for help right away.
Withdrawal seizures
Risk factors: Stopping lacosamide (Vimpat) suddenly
Don't stop taking lacosamide (Vimpat) without talking to your prescriber first. Stopping antiepileptic medications too fast can raise the risk of seizures. These seizures can happen more often or last longer, which can be dangerous.
If you want to stop taking lacosamide (Vimpat), talk to your prescriber. They'll help you do this safely. Usually, they'll slowly lower the dose over at least a week to help prevent seizures from getting worse.
Allergic reactions
In some rare cases, people have had a serious and sometimes life-threatening allergic reaction to lacosamide (Vimpat). It's called Drug Reaction with Eosinophilia and System Symptoms, or DRESS syndrome.
DRESS syndrome can cause fever, rash, swollen lymph nodes, and facial swelling. In serious cases, it can lead to abnormal blood cell counts and damage to parts of your body, like your liver, kidneys, or heart.
Look out for a rash, fever, swollen lymph nodes, flu-like symptoms, swollen face, or trouble breathing. If this happens, stop taking lacosamide (Vimpat) and get medical help right away.
Caution use in people with phenylketonuria (PKU) - oral solution only
The oral solution of lacosamide (Vimpat) has an artificial sweetener called aspartame. This artificial sweetener can be harmful for people who have a genetic condition called phenylketonuria (PKU).
If you or your child has PKU, talk to your prescriber. They can help you find other options that will be safer to take.
What are the side effects of Lacosamide (Vimpat)?
Common Side Effects
- Dizziness (31%)
- Headache (13%)
- Nausea (11%)
- Double vision (11%)
- Vomiting (9%)
- Tiredness (9%)
- Blurred vision (8%)
- Problems with movement or coordination (8%)
- Sleepiness (7%)
- Tremor (7%)
Other Side Effects
- Feeling like the room is spinning
- Weakness
- Trouble walking
- Problems with balance
- Problems with memory
- Diarrhea
- Depression
- Itching
- Bruise
- Shaky eye movements (nystagmus)
Serious Side Effects
- Thoughts of hurting yourself or suicide
- Irregular heartbeat: chest discomfort, palpitations, feeling like you're going to pass out
- Severe allergic reaction: rash; fever; swollen lymph nodes; flu-like symptoms; swelling of the mouth, face, or throat
Source: DailyMed
More on Lacosamide (Vimpat) side effects
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- Heart rhythm changes—fast or irregular heartbeat, dizziness, feeling faint or lightheaded, chest pain, trouble breathing
- Rash, fever, and swollen lymph nodes
- Thoughts of suicide or self-harm, worsening mood, or feelings of depression
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
- Dizziness
- Double vision
- Drowsiness
- Headache
- Loss of balance or coordination
- Nausea
Pros and cons of Lacosamide (Vimpat)
Pros
Can take with other seizure medications
Available as a tablet and oral solution
Okay for children 1 month of age and older with partial-onset seizures and children 4 years and older with PGTC seizures
Cons
Is a controlled substance, so you can only get a limited amount per month
Can cause side effects like dizziness, headache, and double vision
Interacts with many medications, like beta blockers
Pharmacist tips for Lacosamide (Vimpat)
You can take lacosamide (Vimpat) with or without food. Food doesn't affect how well the medication works.
Swallow the lacosamide (Vimpat) tablets whole with some water or another drink. Don't cut the tablets because it could change the way the medication works. If you have trouble swallowing tablets whole, ask your prescriber about switching you to the oral solution.
Lacosamide (Vimpat) can make you feel dizzy, sleepy, or have blurry vision. It commonly happens when you first start taking the medication or when you switch to a higher dose. Be careful when you drive or do anything that needs you to focus well. Make sure you know how lacosamide (Vimpat) affects you first.
Don't stop taking lacosamide (Vimpat) without talking to your prescriber first. Stopping it too suddenly can make your seizures come back, which can be dangerous. If you want to stop, follow your prescriber's directions. They'll usually lower your dose over at least 1 week before stopping it completely.
If you're pregnant or thinking of becoming pregnant, talk to your prescriber or obstetrician-gynecologist (OB-GYN). We don't fully know if lacosamide (Vimpat) is safe during pregnancy. But it's important to control your seizures when pregnant. Your prescriber can help you find the safest seizure medication. If you take a seizure medication during pregnancy, you can join a pregnancy registry to help researchers learn more about the risks.
Tell your prescriber if you plan to breastfeed while taking lacosamide (Vimpat). They can discuss the risks and benefits with you. The medication can pass into breast milk, and it's possible that breastfed babies can have side effects like sleepiness.
Tips for the lacosamide (Vimpat) oral solution:
Keep the lacosamide (Vimpat) oral solution at room temperature (up to 77ºF).
The lacosamide (Vimpat) oral solution is good for 6 months after you open the bottle. Throw out any medication in the bottle that's left after this time. Ask your pharmacist how to safely throw out expired or unused medication.
Ask the pharmacy for a measuring device like an oral syringe to measure out your dose. Don't use household teaspoons or tablespoons because they might not give you the correct dose.
Frequently asked questions about Lacosamide (Vimpat)
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Lacosamide (Vimpat) dosage forms
Typical dosing for Lacosamide (Vimpat)
Adults 17 years and older
Partial-onset seizures (when taken by itself): The typical starting dose is 100 mg by mouth twice daily. Your prescriber will adjust your dose each week if necessary. The maximum dose is 200 mg twice daily.
Add-on therapy for partial-onset or PGTC seizures: The typical starting dose is 50 mg by mouth twice daily. Your prescriber will adjust your dose every week if necessary. The maximum dose is 200 mg twice daily.
Children
Dosing is based on your child's body weight. Your child's prescriber will adjust the dose each week if necessary.
Weigh 110 lbs (50 kg) or more: The starting dose is 50 mg by mouth twice daily. The maximum dose is 200 mg twice daily.
Weigh 66 lbs to less than 110 lbs (30 kg to less than 50 kg): The starting dose is 1 mg/kg of body weight by mouth twice daily. The maximum dose is 4 mg/kg twice daily.
Weigh 24 lbs to less than 66 lbs (11 kg to less than 30 kg): The starting dose is 1 mg/kg of body weight by mouth twice daily. The maximum dose is 6 mg/kg twice daily.
For partial-onset seizures only
Weigh 13 lbs to less than 24 lbs (6 kg to less than 11 kg): The starting dose is 1 mg/kg of body weight by mouth twice daily. The maximum dose is 6 mg/kg twice daily.
Weigh less than 13 lbs (6 kg): The starting dose is 1 mg/kg of body weight by mouth twice daily. The maximum dose is 7.5 mg/kg twice daily.
Your dose might differ if you have liver or severe kidney problems.
Lacosamide (Vimpat) is also available as an injection given through the vein. It's administered by a trained healthcare professional in the hospital.
More on Lacosamide (Vimpat) dosage forms
How much does Lacosamide (Vimpat) cost?
What are alternatives to Lacosamide (Vimpat)?
Partial-onset seizures (or focal aware seizures) - for people at least 1 month of age
Primary generalized tonic-clonic (PGTC) seizures - for people at least 4 years old
Seizures (partial seizures, tonic-clonic seizures)
Seizures of Lennox-Gastaut syndrome - immediate-release only
Bipolar disorder - immediate-release only
Partial-onset seizures (or focal aware seizures)
What is the latest news about Lacosamide (Vimpat)?
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References
Best studies we foundBen-Menachem, E., et al. (2007). Efficacy and safety of oral lacosamide as adjunctive therapy in adults with partial-onset seizures. Epilepsia.
Centers for Disease Control and Prevention. (n.d.). Protect your child: Use the right tool to give the right dose.
Doty, P., et al. (2013). Development of lacosamide for the treatment of partial-onset seizures. Annals of the New York Academy of Sciences.
Kiriakopoulos, E., et al. (n.d.). Focal onset aware seizures (simple partial seizures). Epilepsy Foundation.
Kiriakopoulos, E., et al. (2022). Tonic-clonic seizures. Epilepsy Foundation.
Li, J., et al. (2020). The adverse-effect profile of lacosamide. Expert Opinion on Drug Safety.
MedlinePlus. (2023). Nystagmus.
MedlinePlus. (2023). Pain medications - narcotics.
MedlinePlus. (2023). Phenylketonuria.
MedlinePlus. (2025). Prescription drug misuse.
Patel, S. I., et al. (2015). Management of epilepsy during pregnancy: An update. Therapeutic Advances in Neurological Disorders.
Pitton Rissardo, J., et al. (2023). Antiseizure medication-induced alopecia: A literature review. Medicines.
UCB, Inc. (2025). Vimpat- lacosamide tablet, film coated; Vimpat- lacosamide injection; Vimpat- lacosamide solution [package insert]. DailyMed.
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