Key takeaways:
Lacosamide (Vimpat, Motpoly XR) treats adults and children who experience certain types of seizures. It’s best to avoid sedatives and alcohol with lacosamide, as they can raise the risk of dizziness and drowsiness.
Combining lacosamide with medications that affect heart rate can raise the risk of heart problems. Examples include antiarrhythmics, beta blockers, and calcium channel blockers.
Other lacosamide interactions, including certain antibiotics and grapefruit products, may raise your lacosamide levels. Be sure to check with your prescriber before making medication changes while taking lacosamide.
Save on related medications
Lacosamide (Vimpat, Motpoly XR) is a medication that treats certain types of seizures in adults and children. You may take it alone or in combination with other seizure medications.
Like all medications, lacosamide has some interactions to be aware of. Preparing for possible interactions can help you avoid unwanted side effects or other issues.
Lacosamide interactions at a glance
Below is a list of lacosamide interactions to be aware of. Keep in mind that other interactions are possible. So it’s best to review your medication list with your prescriber or pharmacist before starting lacosamide. They can look for any possible issues and provide guidance to avoid an interaction if needed.
Lacosamide interactions include:
Medications that help manage your heart rhythm (antiarrhythmics)
Sedating medications, such as opioids and benzodiazepines
Some oral antifungal medications, such as fluconazole (Diflucan) and ketoconazole
Some antibiotics, such as clarithromycin (Biaxin) and ciprofloxacin
Some antiviral medications, such as ritonavir (Norvir) and indinavir (Crixivan)
Grapefruit juice
Alcohol
Other anti-seizure medications, such as carbamazepine, phenytoin, and phenobarbital
St. John’s wort
Let’s take a closer look at 6 lacosamide interactions you should know about.
1. Medications that affect your heart rate
Lacosamide can cause a slow or irregular heartbeat in some cases. This side effect isn’t common, but the risk is higher if you take other medications that affect your heart rate, including:
Anti-arrhythmia medications, such as amiodarone (Pacerone), digoxin (Lanoxin), and flecainide
Beta blockers, such as metoprolol (Lopressor, Toprol XL) and carvedilol (Coreg)
Calcium channel blockers, such as amlodipine (Norvasc) and diltiazem (Cardizem, Cartia XT)
If you take a heart-related medication, be sure to let your prescriber know before starting Vimpat. You may need a lower Vimpat dosage or more frequent heart monitoring with this combination.
2. Other anti-seizure medications
Other medications that treat seizures can also interact with lacosamide. The combination may raise your risk of heart issues, as described above. Some anti-seizure medications may also reduce lacosamide levels in the body, making it less effective.
Examples of anti-seizure medications that can interact with lacosamide include:
Phenytoin (Dilantin)
Carbamazepine (Tegretol, Equetro)
Lamotrigine (Lamictal)
Oxcarbazepine (Trileptal, Oxtellar XR)
Lacosamide side effects: Learn more about the side effects of lacosamide (Vimpat, Motpoly XR) and how to manage them.
Vimpat dosages: Review the recommended Vimpat dosages for adults and children.
How much does Vimpat cost without insurance? Here’s what to know about the cost of Vimpat and ways to save on your prescription.
In some cases, you may still need to take lacosamide with one of these anti-seizure medications. In this case, your prescriber will likely keep a close eye on your heart rate and adjust your dosages as needed. Be sure to follow their instructions, and don’t make any changes to your medications without their OK.
3. Sedative medications
Sedative medications help relax the body and mind. Common examples include:
Benzodiazepines, such as alprazolam (Xanax)
Sleep medications, such as zolpidem (Ambien)
Dizziness is a common lacosamide side effect. But combining lacosamide with sedatives can raise the risk of excessive dizziness or drowsiness. This can make falls or other accidental injuries more likely.
It’s best to avoid this combination when possible. But if your prescriber recommends taking a sedative with lacosamide, use extra caution when performing activities that require coordination. And it’s a good idea to avoid driving until you know how the medications affect you.
4. Alcohol
Alcohol interacts with lacosamide in multiple ways. First of all, alcohol has sedative effects. So it can raise the risk of excessive dizziness and drowsiness when combined with lacosamide. Alcohol can also raise your risk of seizures, especially in large amounts or with frequent use.
It’s best to limit or avoid alcohol while taking lacosamide. Your prescriber can help you determine how much, if any, alcohol is safe for you. If needed, they can also provide support to help you cut back on drinking.
5. Some anti-infective medications
Some medications that treat bacterial, fungal, or viral infections can raise lacosamide levels in the body. This can raise the risk of side effects, such as dizziness and vision changes.
Examples include:
Some antibiotics, such as clarithromycin and ciprofloxacin
Some oral antifungals, such as fluconazole and ketoconazole
Some antivirals, such as ritonavir, which is also a component of Paxlovid (nirmatrelvir / ritonavir)
If you require treatment for an infection, be sure your prescriber knows you’re taking lacosamide. They may need to lower your lacosamide dosage or prescribe a different anti-infective medication.
6. Grapefruit
Grapefruit blocks an enzyme (protein) that breaks down lacosamide in the body. Small amounts of grapefruit or grapefruit juice aren’t likely to cause an issue. But if you consume grapefruit in large amounts or on a daily basis, it could raise lacosamide levels and increase your risk of side effects. So it’s best to keep grapefruit to a minimum with this medication. Talk to your prescriber if you have questions about how much grapefruit is safe for you.
The bottom line
Lacosamide (Vimpat, Motpoly XR) is a medication that treats certain types of seizures in adults and children. Lacosamide interactions include medications that can slow your heart rate, such as anti-arrhythmia medications, beta blockers, and calcium channel blockers. Other anti-seizure medications can also make heart issues more likely if combined with lacosamide.
It’s best to avoid taking lacosamide with sedatives or alcohol, as they can make excessive dizziness and drowsiness more likely. Some anti-infective medications and grapefruit products can raise lacosamide levels in the body. Check with your prescriber before starting lacosamide or making any changes to your medications to help ensure your safety.
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References
Aucta Pharmaceuticals. (2025). Motploy XR- lacosamide capsule, extended release [package insert].
Brodie, M. J. (2017). Sodium channel blockers in the treatment of epilepsy. CNS Drugs.
Clinical Pharmacology. (n.d.). Drug interactions flockhart table. Indiana University Department of Medicine.
Epilepsy Foundation. (n.d.). Alcohol.
King, G. S., et al. (2024). Antiarrhythmic medications. StatPearls.
Maadarani, O., et al. (2021). Cardiac sodium channel blockade due to antiepileptic drug combination. European Journal of Case Reports in Internal Medicine.
UCB. (2025). Vimpat- lacosamide tablet, film coated, Vimpat- lacosamide injection, Vimpat- lacosamide solution [package insert].
Yadav, R., et al. (2021). Lacosamide-related arrhythmias: A systematic analysis and review of the literature. Cureus.
