Adults

Initial dose: 500 mg twice daily. This dose may be increased by 500 mg twice daily every 2 weeks to a maximum of 1500 mg twice daily (3000 mg/day).

Elderly

Dose adjustment may be necessary in elderly patients due to potential age-related decrease in renal function. Starting with a lower dose and careful titration is recommended.

Renal_impairment

Dosage must be adjusted based on creatinine clearance (CrCl). For CrCl <80 mL/min, a reduced daily dose is recommended. For severe renal impairment or end-stage renal disease, significant dose reduction and monitoring are required.

Onset

Clinical effects are typically observed within 1 hour of administration.

Excretion

Approximately 66% of the administered dose is excreted in the urine as unchanged drug, and 24% as the inactive metabolite. Renal excretion is the primary route of elimination.

Half life

The plasma elimination half-life is approximately 6-8 hours in adults and children 12 years and older. It is shorter in children 4-12 years (around 4-6 hours).

Absorption

Levetiracetam is rapidly and almost completely absorbed after oral administration. Peak plasma concentrations are reached within 1 hour. Oral bioavailability is approximately 100%.

Metabolism

Levetiracetam is minimally metabolized in humans. It is primarily hydrolyzed in the blood to an inactive carboxylic acid derivative (ucb L057) by enzymatic hydrolysis, not by hepatic cytochrome P450 isoenzymes.

Methotrexate

Concomitant use with Levetiracetam has been reported to decrease methotrexate clearance, leading to increased methotrexate concentration and potential toxicity. Careful monitoring of methotrexate levels is advised.

Other CNS depressants

Concurrent use with other CNS depressants (e.g., alcohol, sedatives) may result in additive sedative effects. Patients should be advised to avoid or limit alcohol intake.