Common Side Effects of Lacosamide
Lacosamide (Vimpat), used for partial-onset seizures, causes dizziness (31% of patients), headache (13%), nausea (7%), and diplopia (double vision, 11%). These occur more often than with placebo.[1][2]
Side Effects More Frequent at Higher Doses
At 400-600 mg/day doses, ataxia (loss of coordination, up to 8%) and balance disorder (6%) rise sharply compared to lower doses or placebo. Tremor affects 4-10% at high doses versus under 2% at 200 mg/day.[1][3]
Differences from Other Antiepileptic Drugs
Unlike carbamazepine or lamotrigine, lacosamide shows less cognitive slowing or sedation but higher rates of vertigo (7-9% vs. 2-4% with levetiracetam). It has minimal weight gain risk compared to valproate.[2][4] No significant rash risk like with phenytoin.
Cardiac Side Effects Unique to Lacosamide
Prolongs PR interval (dose-dependent, up to 20% at 600 mg/day), risking AV block (0.4-1%). FDA warns against use in patients with conduction issues; monitor ECG. Rare with other AEDs except carbamazepine.[1][5]
Side Effects in Special Populations
Pediatrics (4+ years): Somnolence (15%) and vomiting (10%) higher than adults. Elderly: Fall risk doubles due to dizziness (40% vs. 25% overall).[1][2] Pregnancy: No major teratogenicity signals, but registry data limited.[6]
What Happens If Side Effects Occur
Dizziness or diplopia often resolve with dose reduction. Discontinuation due to adverse events: 10-20% in trials, mainly CNS effects. Report persistent issues to clinician; taper slowly to avoid seizures.[1][3]
[1]: Vimpat Prescribing Information (UCB, 2023)
[2]: Epilepsia Journal Review on Lacosamide Safety (2019)
[3]: FDA Label for Vimpat
[4]: Head-to-Head Comparison in Neurology (2021)
[5]: AAN Guideline on AED Cardiac Risks
[6]: North American AED Pregnancy Registry