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Vimpat Side Effects

Generic name: lacosamide

Medically reviewed by Last updated on Mar 7, 2023.

Note: This document contains side effect information about lacosamide. Some dosage forms listed on this page may not apply to the brand name Vimpat.


Common side effects of Vimpat include: blurred vision, diplopia, dizziness, fatigue, headache, nausea, nystagmus disorder, tremor, vomiting, and ataxia. Other side effects include: abnormal gait, asthenia, memory impairment, and vertigo. Continue reading for a comprehensive list of adverse effects.

Applies to lacosamide: oral solution, oral tablet. Other dosage forms:

Serious side effects of Vimpat

Along with its needed effects, lacosamide (the active ingredient contained in Vimpat) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking lacosamide:

More common

  • Dizziness
  • false or unusual sense of well-being
  • shakiness and unsteady walk
  • sleepiness or unusual drowsiness
  • trembling or shaking of the hands or feet
  • unsteadiness, trembling, or other problems with muscle control or coordination

Less common

  • Being forgetful
  • discouragement
  • feeling sad or empty
  • irritability
  • itching skin
  • lack of appetite
  • loss of balance control
  • loss of interest or pleasure
  • mood or mental changes
  • tearing of the skin
  • tiredness
  • trouble concentrating
  • trouble with sleeping
  • trouble with walking

Incidence not known

  • Abnormal or decreased touch sensation
  • black, tarry stools
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • changes in patterns and rhythms of speech
  • chills
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cough
  • fast, irregular, pounding, or racing heartbeat or pulse
  • feeling drunk
  • fever
  • hearing loss
  • lower back or side pain
  • painful or difficult urination
  • pale skin
  • slurred speech
  • sore throat
  • trouble breathing
  • trouble performing routine tasks
  • trouble with balance
  • trouble with speaking
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Other side effects of Vimpat

Some side effects of lacosamide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

  • Diarrhea
  • feeling of constant movement of self or surroundings
  • lack or loss of strength
  • sensation of spinning
  • uncontrolled eye movements

Incidence not known

  • Acid or sour stomach
  • belching
  • blistering, peeling, loosening of the skin
  • constipation
  • difficulty having a bowel movement
  • dry mouth
  • heartburn
  • increased sweating
  • indigestion
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • muscle spasms
  • stomach discomfort, upset, or pain

For Healthcare Professionals

Applies to lacosamide: intravenous solution, oral solution, oral tablet.


The most commonly reported adverse reactions have included diplopia, headache, dizziness, and nausea.

Nervous system

Very common (10% or more): Dizziness (up to 60%), headache (up to 13%), ataxia (up to 15%)

Common (1% to 10%): Somnolence, tremor, balance disorder, nystagmus, memory impairment, coordination abnormal, cognitive disorder, somnolence, tremor, dysarthria, disturbance in attention, paresthesia

Frequency not reported: Oral hypoesthesia, pyrexia

Postmarketing reports: Hypoesthesia, cerebellar syndrome, new or worsening seizures, dyskinesia[Ref]

Dizziness was reported in 25% of patients randomized to the recommended doses (200 to 400 mg/day) of this drug compared with 8% of placebo patients in studies in adult patients with partial-onset seizures taking 1 to 3 concomitant AEDs. It was the event most frequently leading to discontinuation (3%). Ataxia was reported by 6% of patients randomized to the recommended doses (200 to 400 mg/day) compared to 2% in placebo patients. Dizziness and ataxia were also observed in pediatric clinical trials.[Ref]


Very common (10% or more): Nausea (up to 24%), vomiting (up to 16%)

Common (1% to 10%): Diarrhea, constipation, flatulence, dyspepsia, dry mouth[Ref]


Very common (10% or more): Diplopia (up to 16%), blurred vision (up to 16%)[Ref]


Uncommon (0.1% to 1%): Hypersensitivity

Frequency not reported: Multiorgan hypersensitivity reactions (also known as Drug Reaction with Eosinophilia and Systemic Symptoms, or DRESS)[Ref]


Very common (10% or more): Fatigue (up to 15%)

Common (1% to 10%): Asthenia, vertigo, gait disturbance

Frequency not reported: Tinnitus, fall[Ref]


Common (1% to 10%): Injection site pain or discomfort

Uncommon (0.1% to 1%): Irritation, erythema[Ref]


Common (1% to 10%): Depression, confusional state, insomnia

Uncommon (0.1% to 1%): Aggression, agitation, euphoric mood, suicide attempt, suicidal ideation, hallucination

Frequency not reported: Irritability, feeling drunk

Postmarketing reports: Psychotic disorder[Ref]


Common (1% to 10%): Pruritus, rash

Uncommon (0.1% to 1%): Angioedema, urticaria

Frequency not reported: Neutropenia, anemia

Postmarketing reports: Stevens-Johnson syndrome, toxic epidermal necrolysis[Ref]


During clinical trials in adult patients with partial-onset seizures, asymptomatic first-degree atrioventricular (AV) block was observed in 0.4% (4/944) of patients randomized to this drug and 0% (0/364) of placebo patients. One case of profound bradycardia was observed in a patient during a 15-minute 150 mg IV infusion.

In short-term trials in adult patients with diabetic neuropathy, atrial fibrillation occurred in 0.5% of patients (placebo=0%). Syncope occurred in 1.2% of patients (placebo=0%).

A clinical pharmacology study in healthy subjects (n=247) did not shown any QTc interval prolongation or dose-related or clinically important effects on QRS duration. This drug did produce a dose-related increase in mean PR interval; the maximum mean PR interval increase corresponded with Tmax. The placebo-subtracted maximum increase in PR interval was 7.3 ms for the 400 mg/day group and 11.9 ms for the 800 mg/day group. In clinical trials, the placebo-subtracted mean maximum increase in PR interval for a 400 mg/day dose was 3.1 ms in patients with partial-onset seizures and 9.4 ms for patients with diabetic neuropathy.[Ref]

Very common (10% or more): Chest pain (up to 12%)

Common (1% to 10%): Syncope

Uncommon (0.1% to 1%): Atrioventricular block, bradycardia, atrial fibrillation, atrial flutter

Frequency not reported: Palpitations

Postmarketing reports: Cardiac arrhythmias including bradycardia, AV block, and ventricular tachyarrhythmia, which have rarely resulted in asystole, cardiac arrest, and death[Ref]


Common (1% to 10%): Muscle spasms

Frequency not reported: Connective tissue disorders[Ref]


Frequency not reported: Neutropenia, anemia

Postmarketing reports: Agranulocytosis[Ref]


Uncommon (0.1% to 1%): Liver function test abnormal

Frequency not reported: Hepatitis[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Vimpat (lacosamide)." UCB Pharma Inc (2008):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.