Vimpat: Uses, Dosage & Side Effects
An antiepileptic medication containing lacosamide, used for the treatment of focal (partial-onset) seizures and primary generalized tonic-clonic seizures in adults and children
Quick Facts: Vimpat (Lacosamide)
Key Takeaways
- Vimpat (lacosamide) is a prescription antiepileptic medication used as monotherapy or adjunctive treatment for focal seizures and primary generalized tonic-clonic seizures.
- It works through a unique mechanism — selectively enhancing slow inactivation of voltage-gated sodium channels — distinguishing it from older antiepileptic drugs.
- Vimpat must not be used in patients with second- or third-degree AV block due to its effect on cardiac conduction (PR interval prolongation).
- The medication is taken twice daily approximately 12 hours apart, with doses gradually titrated upward from 50 mg twice daily to a maintenance dose of 100–300 mg twice daily.
- Common side effects include dizziness, headache, nausea, and double vision; patients should not drive until they know how the medication affects them.
What Is Vimpat and What Is It Used For?
Vimpat contains the active ingredient lacosamide, a functionalized amino acid that was developed as a novel antiepileptic agent with a mechanism of action distinct from traditional sodium channel blockers. While conventional antiepileptic drugs such as carbamazepine and phenytoin primarily target fast inactivation of sodium channels, lacosamide selectively enhances slow inactivation. This unique pharmacological profile means it can provide additional seizure control when used alongside other antiepileptic medications, as it works through a complementary mechanism.
Lacosamide was first approved by the European Medicines Agency (EMA) in 2008 and has since become a widely prescribed antiepileptic drug worldwide. It is available as the branded product Vimpat as well as several generic formulations, including Lacosamide Krka, Lacosamide Accord, Lacosamide Teva, Lacosamide STADA, Lacosamide Zentiva, Lacosamide Vivanta, and Lacosamide hameln. The availability of generic options has made lacosamide accessible to a broader patient population.
Approved Indications
Vimpat is approved for the treatment of the following types of epilepsy:
- Focal (partial-onset) seizures with or without secondary generalization — as monotherapy or adjunctive therapy in adults, adolescents, and children from 2 years of age. In this type of epilepsy, seizures initially affect only one side of the brain but may subsequently spread to involve both hemispheres.
- Primary generalized tonic-clonic seizures — as adjunctive therapy in adults, adolescents, and children from 4 years of age with idiopathic generalized epilepsy (a form of epilepsy that is believed to have a genetic basis). These are major seizures involving loss of consciousness and whole-body convulsions.
Clinical trials have demonstrated that lacosamide significantly reduces seizure frequency when added to existing antiepileptic regimens. In pivotal phase III trials involving patients with uncontrolled focal seizures, lacosamide at doses of 200 mg/day and 400 mg/day achieved a median seizure reduction of approximately 33–40% compared to 10–20% with placebo. More recently, the monotherapy indication was supported by a historical-control conversion-to-monotherapy trial and a head-to-head non-inferiority study comparing lacosamide with controlled-release carbamazepine.
Lacosamide is also available as an intravenous formulation (10 mg/ml solution for infusion), which allows for temporary parenteral administration when oral intake is not possible, such as during surgical procedures or acute illness. The intravenous formulation provides a one-to-one dose equivalence with the oral tablets, simplifying the transition between routes of administration.
What Should You Know Before Taking Vimpat?
Contraindications
You must not take Vimpat if:
- You are allergic to lacosamide or any of the other ingredients in the medication.
- You have a known type of heart rhythm disorder called second-degree or third-degree atrioventricular (AV) block. This is because lacosamide can prolong the PR interval on an electrocardiogram (ECG), and the combination with existing AV block could lead to dangerous heart rhythm disturbances.
Vimpat can cause dose-dependent prolongation of the PR interval. Cases of second- and third-degree AV block, including complete heart block, have been reported in post-marketing surveillance. Patients with known cardiac conduction problems, those taking PR-prolonging drugs, or those with severe cardiac disease (such as a history of heart attack or heart failure) should be closely monitored with ECG before dose increase and at steady state.
Warnings and Precautions
Talk to your doctor before taking Vimpat if any of the following apply to you:
- Suicidal thoughts or behavior: A small number of people treated with antiepileptic drugs, including lacosamide, have experienced suicidal ideation. If you ever experience such thoughts, contact your doctor immediately. The FDA and EMA have both issued advisories regarding this class-wide effect of antiepileptic medications.
- Heart problems: If you have cardiac conditions affecting your heartbeat, including a frequently slow, fast, or irregular heart rate (such as atrial fibrillation or atrial flutter), Vimpat should be used with particular caution. An ECG is recommended before starting treatment and after dose titration is complete.
- Severe cardiac disease: If you have heart failure or a history of myocardial infarction (heart attack), discuss the risks and benefits carefully with your doctor.
- Dizziness and falls: Vimpat may cause dizziness, which can increase the risk of accidents and falls. Be cautious until you are familiar with how the medication affects you, particularly during the initial dose titration period and after dose increases.
While taking Vimpat, you should inform your doctor if you experience a new type of seizure or worsening of your existing seizure pattern. Additionally, if you develop symptoms of abnormal heartbeat — such as slow, fast, or irregular pulse, palpitations, shortness of breath, dizziness, or fainting — seek medical attention immediately.
Pregnancy and Breastfeeding
Vimpat is not recommended during pregnancy because the effects on pregnancy and the developing fetus are not fully established. Animal studies have shown reproductive toxicity, and there is insufficient clinical data in pregnant women. Women of childbearing potential should discuss suitable contraception with their doctor before starting treatment.
It is also not recommended to breastfeed while taking Vimpat, as lacosamide is excreted in human breast milk. The potential for serious adverse reactions in the nursing infant has not been fully evaluated.
If you become pregnant or plan to become pregnant, contact your doctor immediately. Do not stop taking Vimpat without medical advice, as abrupt discontinuation can lead to increased seizure frequency (rebound seizures), which can also be harmful to you and your unborn child. Your doctor will help you weigh the risks and benefits and decide whether to continue treatment.
Driving and Operating Machinery
You should not drive, cycle, or operate tools or machinery until you know how Vimpat affects you. This is because the medication can cause dizziness and blurred vision, which may impair your ability to perform these activities safely. If you experience such side effects, avoid these activities until the symptoms resolve. Note that epilepsy itself can also restrict your ability to drive, and you should follow your country's regulations regarding driving with epilepsy.
Alcohol
As a precautionary measure, you should avoid consuming alcohol while taking Vimpat. Alcohol may enhance the central nervous system depressant effects of lacosamide, potentially increasing the risk of dizziness, drowsiness, and impaired coordination.
How Does Vimpat Interact with Other Drugs?
Drug interactions with lacosamide occur through two main pathways: pharmacodynamic interactions (where combined effects on the heart or nervous system are additive) and pharmacokinetic interactions (where other drugs alter the blood levels of lacosamide, or vice versa). Understanding these interactions is essential for safe and effective therapy.
Major Interactions: Cardiac Risk
The most clinically important interactions involve medications that can prolong the PR interval on an ECG. When combined with Vimpat, these drugs may increase the risk of AV block and other cardiac conduction disturbances. These include:
- Antiepileptic drugs that prolong PR interval: carbamazepine, lamotrigine, pregabalin, and eslicarbazepine. If you are taking any of these alongside Vimpat, your doctor may recommend periodic ECG monitoring.
- Cardiac medications: Beta-blockers, calcium channel blockers (such as verapamil and diltiazem), digoxin, and antiarrhythmic drugs (such as amiodarone and flecainide).
- Other PR-prolonging agents: Certain antidepressants, antipsychotics, and other drugs known to affect cardiac conduction.
Pharmacokinetic Interactions
Lacosamide is primarily metabolized by the CYP2C19 enzyme and is also partly eliminated unchanged by the kidneys. The following drugs may alter lacosamide blood levels:
| Interacting Drug | Effect on Vimpat | Clinical Significance | Recommendation |
|---|---|---|---|
| Fluconazole | May increase lacosamide levels | CYP2C19 inhibitor | Monitor for increased side effects |
| Itraconazole / Ketoconazole | May increase lacosamide levels | CYP3A4 inhibitor | Use with caution; monitor |
| Ritonavir | May increase lacosamide levels | Potent CYP3A4/CYP2C19 inhibitor | Dose adjustment may be needed |
| Clarithromycin | May increase lacosamide levels | CYP3A4 inhibitor | Monitor for side effects |
| Rifampicin | May decrease lacosamide levels | Potent enzyme inducer | Dose increase may be needed |
| St. John's Wort | May decrease lacosamide levels | Enzyme inducer | Avoid combination |
| Carbamazepine | May decrease lacosamide levels + PR prolongation risk | Enzyme inducer + cardiac effect | ECG monitoring; dose adjustment |
Lacosamide itself has low potential for causing pharmacokinetic interactions with other drugs. In clinical studies, lacosamide did not significantly affect plasma concentrations of commonly used antiepileptic drugs such as carbamazepine, valproic acid, levetiracetam, topiramate, lamotrigine, or zonisamide. It also does not significantly affect the metabolism of oral contraceptives (ethinylestradiol and levonorgestrel), warfarin, or metformin.
What Is the Correct Dosage of Vimpat?
Always take Vimpat exactly as your doctor has prescribed. The dose is individualized based on seizure control and tolerability. Lacosamide is used as a long-term treatment, and you should continue taking it until your doctor advises you to stop. Never change your dose or stop the medication without consulting your healthcare provider first.
Adults and Adolescents/Children Weighing 50 kg or More
Monotherapy (Vimpat as sole antiepileptic)
- Starting dose: 50 mg twice daily (or 100 mg twice daily as prescribed by your doctor)
- Titration: Increase by 50 mg twice daily each week
- Maintenance dose: 100–300 mg twice daily
Adjunctive Therapy (Vimpat added to other antiepileptics)
- Starting dose: 50 mg twice daily
- Titration: Increase by 50 mg twice daily each week
- Maintenance dose: 100–200 mg twice daily
- Optional loading dose: If weighing 50 kg or more, your doctor may start treatment with a single loading dose of 200 mg, followed by the regular maintenance dose 12 hours later
Children and Adolescents Weighing Less Than 50 kg
For children and adolescents weighing under 50 kg, the dose is calculated based on body weight. Treatment is usually initiated with the oral syrup formulation and only switched to tablets when the child is able to take tablets and the correct dose can be achieved with available tablet strengths. Your doctor will prescribe the most suitable formulation.
Vimpat is not recommended for children under 2 years of age for the treatment of focal seizures, and not recommended for children under 4 years of age for the treatment of primary generalized tonic-clonic seizures. There is insufficient data on efficacy and safety in these younger age groups.
Dosage in Special Populations
| Population | Dosage Adjustment | Maximum Dose |
|---|---|---|
| Mild to moderate renal impairment | No adjustment required | Standard dosing |
| Severe renal impairment (CrCl ≤30 ml/min) | Maximum 250 mg/day recommended | 250 mg/day |
| Hemodialysis patients | Supplementary dose of up to 50% after dialysis | Per physician guidance |
| Mild to moderate hepatic impairment | Caution during titration; max 300 mg/day | 300 mg/day |
| Severe hepatic impairment | Not recommended | N/A |
| Elderly patients | No specific adjustment; consider age-related renal decline | Standard dosing with caution |
Missed Dose
If you have missed a dose of Vimpat:
- Less than 6 hours since the scheduled dose: Take it as soon as you remember.
- More than 6 hours since the scheduled dose: Skip the missed dose and take your next dose at the normal time.
- Never take a double dose to make up for a forgotten one.
Overdose
If you have taken too much Vimpat, contact your doctor or emergency services immediately. Symptoms of overdose may include dizziness, nausea, vomiting, seizures, cardiac arrhythmias (slow, fast, or irregular heartbeat), coma, and hypotension with rapid heartbeat and sweating. There is no specific antidote; treatment is supportive. Hemodialysis effectively removes lacosamide from the body (approximately 50% in 4 hours).
Stopping Treatment
Do not stop taking Vimpat without consulting your doctor. If your doctor decides to end your treatment, the dose will be gradually reduced over at least one week. Abrupt discontinuation of any antiepileptic drug, including lacosamide, can lead to rebound seizures, which may be more frequent or severe than before treatment.
What Are the Side Effects of Vimpat?
Like all medicines, Vimpat can cause side effects, although not everyone experiences them. Side effects affecting the central nervous system, such as dizziness, may be more pronounced after a loading dose. The side effects listed below are based on data from clinical trials and post-marketing surveillance.
Very Common
May affect more than 1 in 10 people
- Headache
- Dizziness or feeling lightheaded
- Nausea
- Double vision (diplopia)
Common
May affect up to 1 in 10 people
- Myoclonic seizures (sudden, brief involuntary muscle jerks)
- Difficulty coordinating movements or walking (ataxia)
- Balance problems, tremor, tingling (paraesthesia), muscle spasms
- Memory difficulties, confusion, difficulty thinking or finding words
- Rapid, uncontrolled eye movements (nystagmus), blurred vision
- Vertigo (spinning sensation), feeling of intoxication
- Vomiting, dry mouth, constipation, indigestion, excessive gas, diarrhea
- Decreased sensation or sensitivity, difficulty articulating words
- Tinnitus (ringing, buzzing, or whistling in the ears)
- Irritability, difficulty sleeping (insomnia), depression
- Drowsiness (somnolence), fatigue or weakness (asthenia)
- Itching (pruritus), skin rash
- Tendency to fall and bruise easily
Uncommon
May affect up to 1 in 100 people
- Slow heart rate (bradycardia), palpitations, irregular pulse
- Other changes in the heart's electrical activity (conduction disorders)
- Euphoria (exaggerated sense of well-being), hallucinations
- Allergic reaction to the medication, hives (urticaria)
- Blood tests showing abnormal liver function, liver damage
- Suicidal thoughts or self-harm ideation
- Anger or agitation, abnormal thinking
- Severe allergic reaction causing swelling of face, throat, hands, or feet (angioedema)
- Fainting (syncope)
- Abnormal involuntary movements (dyskinesia)
Not Known
Frequency cannot be estimated from available data
- Abnormally fast heart rhythm from the ventricles (ventricular tachyarrhythmia)
- Agranulocytosis: sore throat, high fever, and more infections than normal (severe decrease in white blood cells)
- Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): high fever, skin rash, swollen lymph nodes, elevated liver enzymes and eosinophils
- Stevens-Johnson syndrome and toxic epidermal necrolysis: widespread rash with blisters and skin peeling, particularly around mouth, nose, eyes, and genitals
- Seizures (paradoxical effect)
Additional Side Effects in Children
In clinical trials involving children, the following additional side effects were observed: fever (pyrexia), runny nose (nasopharyngitis), sore throat (pharyngitis), decreased appetite, behavioral changes, abnormal behavior, and lack of energy (lethargy). Drowsiness (somnolence) is a very common side effect in children and may affect more than 1 in 10.
Contact your doctor or seek emergency medical care immediately if you experience: symptoms of an allergic reaction (difficulty breathing, swelling of face or throat, severe rash), signs of cardiac problems (fainting, palpitations, very slow or irregular heartbeat), suicidal thoughts, or signs of a severe skin reaction (widespread rash with blisters or skin peeling).
How Should You Store Vimpat?
Vimpat film-coated tablets should be stored at room temperature. There are no special storage requirements regarding temperature or humidity for the tablet formulation. Keep the medication in its original packaging to protect it from light and moisture.
Keep all medicines out of the sight and reach of children. Do not use Vimpat after the expiry date stated on the carton and blister after "EXP." The expiry date refers to the last day of that month.
Do not dispose of medications in wastewater or household waste. Ask your pharmacist about how to properly dispose of medications that are no longer needed. These measures help protect the environment. If you are switching between the branded Vimpat product and a generic lacosamide formulation, ensure you follow the same storage instructions provided with the specific product.
What Does Vimpat Contain?
Each Vimpat tablet contains lacosamide as the active substance, along with inactive ingredients (excipients) that make up the tablet core and film coating. The tablet core consists of microcrystalline cellulose, hydroxypropylcellulose, low-substituted hydroxypropylcellulose, colloidal anhydrous silica, crospovidone, and magnesium stearate.
The film coating contains polyvinyl alcohol, polyethylene glycol, talc, titanium dioxide (E171), and colorants specific to each strength:
| Strength | Color | Markings | Approximate Size |
|---|---|---|---|
| 50 mg | Pinkish | 'SP' on one side, '50' on the other | 10.4 mm × 4.9 mm |
| 100 mg | Dark yellow | 'SP' on one side, '100' on the other | 13.2 mm × 6.1 mm |
| 150 mg | Salmon pink | 'SP' on one side, '150' on the other | 15.1 mm × 7.0 mm |
| 200 mg | Blue | 'SP' on one side, '200' on the other | 16.6 mm × 7.8 mm |
Vimpat is supplied in pack sizes of 14, 28, 56, 60, 14 × 1, and 56 × 1 film-coated tablets. The 50 mg and 100 mg tablets are also available in packs of 168 tablets. The 150 mg and 200 mg tablets are available in multipacks consisting of 3 packs of 56 tablets each. Not all pack sizes may be marketed in all countries.
The solution for infusion contains lacosamide 10 mg/ml and is supplied in single-use vials for intravenous administration in hospital settings. It is intended for short-term use when oral administration is temporarily not possible.
Frequently Asked Questions About Vimpat
Vimpat is the original brand name for lacosamide, manufactured by UCB Pharma. Generic versions such as Lacosamide Krka, Lacosamide Accord, Lacosamide Teva, and others contain the same active ingredient (lacosamide) at the same dose and must meet the same regulatory standards for quality, safety, and bioequivalence. The main differences are typically in price, packaging, and appearance (tablet color and shape). Clinically, they are expected to produce the same therapeutic effect. However, some patients may be sensitive to changes in inactive ingredients (excipients) between brands, so always discuss any switch with your doctor or pharmacist.
Yes, Vimpat tablets can be taken with or without food. Food does not significantly affect the absorption of lacosamide. The tablets should be swallowed whole with a glass of water. It is recommended to take Vimpat at approximately the same times each day, roughly 12 hours apart, to maintain consistent blood levels of the medication.
Lacosamide begins to work soon after reaching adequate blood levels, but the full therapeutic effect is typically assessed once the target maintenance dose has been achieved — usually after several weeks of gradual dose titration. The dose is increased slowly (typically by 50 mg twice daily each week) to minimize side effects. Some patients may notice a reduction in seizure frequency during the titration phase, while for others the full benefit becomes apparent at the maintenance dose. Your doctor will evaluate your response after an adequate trial period.
Weight gain is not listed as a common side effect of Vimpat in clinical trial data. Unlike some other antiepileptic drugs (such as valproic acid or pregabalin), lacosamide is considered relatively weight-neutral. Some patients may experience decreased appetite as a side effect, but this is uncommon. If you notice significant weight changes while taking Vimpat, discuss this with your doctor to evaluate potential causes.
It is recommended to avoid alcohol while taking Vimpat. Alcohol can enhance the central nervous system depressant effects of lacosamide, potentially worsening side effects such as dizziness, drowsiness, and impaired coordination. Additionally, alcohol can lower the seizure threshold, potentially counteracting the anti-seizure effect of the medication. If you have questions about alcohol consumption, discuss them with your doctor.
No specific dose adjustment is required for elderly patients based on age alone. However, age-related decline in kidney function should be considered, as lacosamide is partly excreted by the kidneys. Elderly patients may also be more susceptible to side effects such as dizziness and falls, and may be taking other medications that could interact with Vimpat (particularly cardiac medications). Careful dose titration and monitoring are advisable in older adults. Your doctor may start with a lower dose and increase it more slowly.
References
- European Medicines Agency (EMA). Vimpat — Summary of Product Characteristics. Last updated 2025. Available at: www.ema.europa.eu/en/medicines/human/EPAR/vimpat
- U.S. Food and Drug Administration (FDA). Vimpat (lacosamide) Prescribing Information. UCB, Inc. Revised 2024.
- Ben-Menachem E, et al. Efficacy and safety of lacosamide as adjunctive therapy in adults with partial-onset seizures. Epilepsia. 2007;48(7):1308–1317.
- Halász P, et al. Adjunctive lacosamide for partial-onset seizures: efficacy and safety results from a randomized controlled trial. Epilepsia. 2009;50(3):443–453.
- Baulac M, et al. Efficacy and tolerability of lacosamide monotherapy versus controlled-release carbamazepine in patients with newly diagnosed epilepsy. Lancet Neurology. 2017;16(1):43–54.
- International League Against Epilepsy (ILAE). Updated ILAE evidence review of antiseizure medication efficacy and effectiveness. Epilepsia. 2022;63(1):12–17.
- National Institute for Health and Care Excellence (NICE). Epilepsies in children, young people and adults. NICE guideline [NG217]. Last updated 2024.
- World Health Organization (WHO). WHO Model List of Essential Medicines — 23rd List. 2023.
- Cawello W, et al. Pharmacokinetics of lacosamide. Clinical Pharmacokinetics. 2012;51(6):371–380.
- Sake JK, et al. A pooled analysis of lacosamide clinical trial data for the treatment of focal seizures. Acta Neurologica Scandinavica. 2010;122(2):86–94.
Medical Editorial Team
Medical Content
Written by iMedic's medical editorial team, specialist physicians in neurology and clinical pharmacology.
Medical Review
Reviewed by the iMedic Medical Review Board according to international guidelines (WHO, EMA, FDA, ILAE, NICE).
Evidence Standard
Level 1A evidence based on systematic reviews, randomized controlled trials, and international treatment guidelines.
Independence
No pharmaceutical company funding or advertising. Fully independent medical editorial content.
Last medical review: | Next scheduled review: