LACOSAMIDE

Clinical safety rating: caution

Animal studies have proved adverse effects but may be safe for humans

How it works

Selectively enhances slow inactivation of voltage-gated sodium channels, stabilizing hyperexcitable neuronal membranes and inhibiting repetitive neuronal firing.

What the body does with it

Metabolism	Approximately 40% of dose excreted unchanged in urine. Major metabolic pathway is O-desmethylation via CYP2C19, CYP3A4, and CYP2C9 to inactive metabolite. Minor pathways include glucuronidation and hydroxylation.
Excretion	Renal: approximately 95% (40% unchanged, remainder as O-desmethyl metabolite). Fecal: <5%.
Half-life	Terminal elimination half-life is approximately 13 hours (range 12–16 hours) in adults. Steady state achieved after 3 days with BID dosing.
Protein binding	Less than 15% bound to plasma proteins (primarily albumin).
Volume of Distribution	Approximately 0.6 L/kg (range 0.5–0.8 L/kg), suggesting distribution into total body water.
Bioavailability	Oral: approximately 100% (highly absorbed). IV: 100%.
Onset of Action	Oral: approximately 1–2 hours post-dose (peak concentrations at 1–4 hours). IV: immediate (administered as infusion, onset within minutes).
Duration of Action	Approximately 12 hours, consistent with twice-daily dosing. Clinical effect persists throughout dosing interval.

Classification & Brands

Dosing & administration

Oral or IV: 50 mg twice daily initially; increase by 50 mg twice daily weekly to maintenance 100-200 mg twice daily. Maximum 200 mg twice daily.

Dosage form	SOLUTION
Renal impairment	CrCl >30 mL/min: No adjustment. CrCl ≤30 mL/min: Max 300 mg/day (150 mg twice daily). Hemodialysis: Max 300 mg/day, supplement 50% of dose after dialysis.
Liver impairment	Mild to moderate (Child-Pugh A or B): Max 300 mg/day (150 mg twice daily). Severe (Child-Pugh C): Not recommended.
Pediatric use	Weight ≥50 kg: 50 mg orally twice daily; titrate by 50 mg twice daily weekly to 100-200 mg twice daily. Weight 30-49 kg: 1 mg/kg twice daily initial; titrate by 1 mg/kg twice daily weekly to 2-4 mg/kg twice daily (max 200 mg twice daily). Weight 11-29 kg: 1 mg/kg twice daily initial; titrate by 1 mg/kg twice daily weekly to 2-4 mg/kg twice daily (max 100 mg twice daily).
Geriatric use	Start at 25-50 mg twice daily based on creatinine clearance; titrate slowly. Monitor for CNS effects, hyponatremia, and arrhythmias.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

No significant drug interactions May cause dizziness and PR interval prolongation.

Breastfeeding	Lacosamide is excreted into breast milk with an estimated M/P ratio of approximately 0.5 to 0.8. Infant exposure is likely low (relative infant dose <10%), but monitor for drowsiness, poor feeding, and weight gain. Weigh benefits against potential risks.
Teratogenic Risk	First trimester: Increased risk of major congenital malformations (neural tube defects, cleft palate, cardiac defects) based on animal studies and limited human data. Second and third trimesters: Potential for fetal growth restriction, neurodevelopmental effects, and neonatal withdrawal syndrome. Late third trimester: Risk of neonatal hemorrhage due to vitamin K depletion.

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning.

Side Effect Profile

Common Effects	Dizziness Headache Nausea Sleepiness Vomiting Visual disturbance Dryness in mouth Muscle spasm
Serious Effects

Absolute Contraindications

["Hypersensitivity to lacosamide or any component of the formulation","Known second- or third-degree atrioventricular (AV) block unless paced"]

Clinical Precautions

Precautions

["Cardiac conduction abnormalities (PR interval prolongation, risk of second/third degree AV block), especially in patients with known conduction problems or on sodium channel blockers","Suicidal behavior and ideation (antiepileptic drugs class warning)","Dizziness, ataxia, and syncope with rapid dose titration","Risk of antiepileptic drug hypersensitivity syndrome (rare)","Monitor electrocardiogram (ECG) in patients with cardiac risk factors"]

Clinical Tips & Counseling

Drug interactions

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