Adults

Initial dose 50 mg twice daily; may be increased by 50 mg twice daily increments every week to a maximum recommended dose of 200 mg twice daily (400 mg/day). Rapid titration: Initial 100 mg twice daily, increasing to 200 mg twice daily after 1 week.

Elderly

No specific dose adjustments needed based on age alone, but caution with renal/hepatic impairment. Start with lower doses if elderly patients have comorbidities.

Renal_impairment

For patients with mild to moderate renal impairment (creatinine clearance [CLcr] 30-80 mL/min), no dose adjustment is required. For severe renal impairment (CLcr < 30 mL/min) and End-Stage Renal Disease (ESRD), a maximum dose of 300 mg/day is recommended. Supplemental doses may be considered after hemodialysis.

Onset

Therapeutic effects typically observed within a few hours to days, depending on individual response and dose titration.

Excretion

Mainly renal, with about 95% of the dose excreted in urine (approximately 40% as unchanged drug, 30% as O-desmethyl-lacosamide, and the remainder as other minor metabolites).

Half life

Approximately 13 hours.

Absorption

Rapid and complete oral absorption with peak plasma concentrations (Cmax) achieved between 0.5 to 4 hours post-dose. Bioavailability is approximately 100%.

Metabolism

Primarily hepatic metabolism by CYP2C19, CYP3A4, and CYP2B6 to inactive metabolites. The major metabolite is O-desmethyl-lacosamide, which has minimal pharmacological activity.

Alcohol

May enhance CNS depressant effects of lacosamide.

Drugs that prolong PR interval

Coadministration with other drugs known to prolong the PR interval (e.g., carbamazepine, lamotrigine, phenytoin, class I antiarrhythmics like lidocaine, propafenone, flecainide) should be done with caution. ECG monitoring may be recommended.

Strong CYP2C19 inhibitors/inducers

Lacosamide is metabolized by CYP2C19, CYP3A4, and CYP2B6. Strong inhibitors (e.g., fluconazole, fluvoxamine) or inducers (e.g., rifampicin, St. John's Wort) of these enzymes may affect lacosamide levels, but clinically significant interactions are generally rare due to alternative metabolic pathways.