Adults

Initial dose of 50 mg twice daily (BID), increased by 50 mg BID weekly to a target dose of 100-200 mg BID. Max dose 400 mg/day. (Note: 4 mg is an unusual strength and typical dosing starts higher; individual titration required.)

Elderly

No specific dose adjustment is generally required for elderly patients based on age alone, but caution is advised due to potential age-related decrease in renal clearance and increased cardiovascular risk.

Renal_impairment

For patients with mild to moderate renal impairment (creatinine clearance 30-80 mL/min), no dose adjustment is necessary. For severe renal impairment (creatinine clearance < 30 mL/min) and end-stage renal disease, a maximum dose of 300 mg/day is recommended. Supplementation after hemodialysis may be needed.

Onset

Clinical effect generally observed within hours to days of initiating therapy, depending on dose titration.

Excretion

Mainly excreted by the kidneys, with approximately 95% of the dose recovered in the urine (around 40% as unchanged drug and 30% as the inactive O-desmethyl metabolite).

Half life

Approximately 13 hours.

Absorption

Rapid and complete absorption after oral administration, with peak plasma concentrations occurring 1-4 hours post-dose.

Metabolism

Primarily metabolized by hydrolysis (major pathway) and cytochrome P450 (CYP2C19, CYP3A4, and CYP2B6) mediated oxidative metabolism. O-demethylation is the major metabolic pathway.

Drugs prolonging PR interval

Concurrent use with drugs that prolong the PR interval (e.g., beta-blockers, calcium channel blockers, digoxin) may increase the risk of cardiac adverse events. ECG monitoring may be required.

Strong CYP2C19 inhibitors/inducers

Although CYP2C19 plays a minor role in lacosamide metabolism, strong inhibitors (e.g., fluconazole, fluvoxamine) or inducers (e.g., rifampicin, St. John's Wort) may potentially alter lacosamide plasma concentrations. Clinical monitoring is advised.