Short answer: Lacosamide (Vimpat) is a prescription antiseizure medicine for partial-onset seizures and, as add-on therapy, generalized tonic-clonic seizures. It is a Schedule V controlled substance because high doses caused euphoria in studies. It can slow electrical conduction in the heart.
Key takeaways
- What it is: Lacosamide is an antiseizure medicine (sodium channel modulator) and a Schedule V controlled substance in the US.
- Main uses: Partial-onset and generalized tonic-clonic seizures.
- Timing: effects start in peak levels in 1 to 4 hours and last twice-daily dosing.
- Most dangerous mix: Drugs that prolong the PR interval (beta blockers, calcium channel blockers, other sodium channel blockers), which can cause heart block, slow heartbeat.
- Naloxone: it does not reverse this drug, but give it whenever opioids could be involved.
- Dependence risk: Low.
- Legal route: only with a prescription from a DEA-registered clinician, filled by a licensed pharmacy.
What is lacosamide?
Lacosamide treats focal (partial-onset) seizures alone or with other medicines, and is added to other treatment for primary generalized tonic-clonic seizures.
It is available as an injection for use when people cannot take it by mouth, and generics have been available since 2022.
Quick facts
| Fact | Lacosamide |
|---|---|
| Generic name | Lacosamide |
| Brand names | Vimpat; Motpoly XR (extended release) |
| Drug class | Antiseizure medicine; enhances slow inactivation of sodium channels |
| US legal status | Schedule V, prescription only |
| Approved uses | Partial-onset seizures (age 1 month and older); add-on for primary generalized tonic-clonic seizures (age 4 and older) |
| Forms | Tablets, oral solution, injection, extended-release capsules |
| Half-life | About 13 hours |
How long does lacosamide last?
- Starts working: Peak levels in 1 to 4 hours
- Effects last: Twice-daily dosing
- Half-life: About 13 hours
Timing varies with the dose, the form, how it is taken, liver and kidney function, age, and other drugs taken at the same time.
What are the biggest risks of lacosamide?
Common side effects include dizziness, double vision, headache, nausea, and unsteadiness.
Heart conduction: it lengthens the PR interval and can cause heart block, slow heartbeat, or atrial fibrillation, especially in people with heart disease. An ECG may be done before and after starting.
Mood: like all antiseizure medicines, it carries a warning about a small increase in suicidal thoughts and behavior. Report new or worsening depression, anxiety, or agitation.
What should you never mix with lacosamide?
| Combined with | What happens | Label guidance |
|---|---|---|
| Drugs that prolong the PR interval (beta blockers, calcium channel blockers, other sodium channel blockers) | Heart block, slow heartbeat | Monitor with ECG |
| Alcohol and sedatives | More dizziness and drowsiness | Use caution |
| Strong CYP3A4 or CYP2C9 inhibitors with kidney or liver impairment | Higher lacosamide levels | Dose reduction may be needed |
Check any combination with the DoseUses combination checker or ask a pharmacist.
What are the signs of a lacosamide overdose, and what should you do?
Overdose causes dizziness, nausea, seizures, and heart conduction problems, including heart block and cardiac arrest at very high doses.
If someone may have taken too much
- Call 911 for fainting, a seizure, chest pain, a racing or irregular heartbeat, confusion, or if the person cannot be woken.
- If the person collapses and is not breathing normally, start CPR and use an AED if one is available.
- Give naloxone if opioids could be involved. It is safe even if they are not.
- For advice when the person is awake and stable, call Poison Help at 1-800-222-1222 (US, free, 24 hours). Bring the product packaging to the hospital.
What happens if you stop lacosamide suddenly?
Lacosamide has low misuse potential, which is why it is in Schedule V. The main danger of stopping suddenly is not withdrawal but a rise in seizures.
- DaysSeizure riskSeizures can return or become more frequent, including prolonged seizures.
- TaperGradual reductionThe label advises tapering over at least a week or longer.
- OngoingReassessChanges in seizure medicines should be planned with a neurologist.
See the withdrawal timelines and the full lacosamide withdrawal guide.
Is lacosamide legal?
In the United States, lacosamide is a Schedule V controlled substance. The only legal way to get it is with a prescription from a clinician registered with the Drug Enforcement Administration (DEA), filled by a licensed pharmacy. Depending on state law, that can be a physician, nurse practitioner, or physician assistant.
- Refills: Schedule V prescriptions can be refilled as the prescriber authorizes, subject to state law.
- Telehealth: federal flexibilities let DEA-registered clinicians prescribe Schedule II to V medicines after a telemedicine visit, without a prior in-person exam, through December 31, 2026. A permanent DEA rule was under final review in late 2026. State rules can be stricter.
- Monitoring: prescribers and pharmacists in most states check a prescription drug monitoring program, a database of controlled-substance prescriptions, before prescribing or dispensing.
Outside the United States
| Country | Status |
|---|---|
| United Kingdom | Prescription-only medicine; not controlled |
| European Union | Prescription only |
| International | Not under UN control |
Frequently asked questions about lacosamide
Why is Vimpat a controlled substance?
In studies, high doses caused euphoria in some people, so the DEA placed it in Schedule V, the lowest schedule.
Does lacosamide affect the heart?
It can slow electrical conduction. People with heart disease may need an ECG before starting.
Can lacosamide make you dizzy?
Yes. Dizziness and double vision are the most common side effects, especially at higher doses.
Is lacosamide used in status epilepticus?
It is sometimes given intravenously off-label for prolonged seizures.
Can you stop lacosamide suddenly?
No. It should be tapered to avoid breakthrough seizures.
Sources
- Vimpat (lacosamide) prescription information, DailyMed, US National Library of Medicine.
- Controlled Substance Schedules, DEA Diversion Control Division.
- Prescribing controlled substances via telehealth, US Department of Health and Human Services.
- BeSafeRx: Your Source for Online Pharmacy Information, US Food and Drug Administration.
- Safe Pharmacy, National Association of Boards of Pharmacy.
- One Pill Can Kill, US Drug Enforcement Administration.
- International drug control conventions, United Nations Office on Drugs and Crime.
This guide summarizes the sourced DoseUses Lacosamide profile, written from FDA labels, DEA rules, and federal health agencies. It is educational and is not medical advice. Last updated October 5, 2026.
