Adults

Initial dose 500 mg twice daily. Can be increased by 500 mg twice daily every 2-4 weeks to a maximum of 1500 mg twice daily. Oral solution can be administered using a calibrated measuring device.

Elderly

Similar to adults, but dosage adjustment may be necessary in elderly patients with impaired renal function.

Renal_impairment

Dose adjustment is required. Dosage should be reduced based on creatinine clearance. For example, severe renal impairment (CrCl < 30 mL/min) may require a dose of 250-500 mg once daily.

Onset

Antiepileptic effects are typically observed within a few days of initiation and dose titration.

Excretion

Mainly via renal excretion (approximately 95% of the dose within 48 hours), with unchanged drug accounting for about two-thirds of the excreted dose.

Half life

Approximately 6-8 hours in adults. Shorter in children (around 5-7 hours).

Absorption

Rapid and almost complete absorption after oral administration. Peak plasma concentrations are achieved approximately 1 hour after administration.

Metabolism

Primarily by enzymatic hydrolysis of the acetamide group, not via cytochrome P450 isoenzymes. Two inactive metabolites are formed.

Phenytoin

Levetiracetam does not appear to affect the pharmacokinetics of other antiepileptic drugs, including phenytoin. However, co-administration may alter the plasma levels of some antiepileptics.

Oral contraceptives

Levetiracetam does not influence the pharmacokinetics of oral contraceptives.