Novel Antiepileptic Drug Approved for Partial Seizures
The pharmacokinetic profile of levetiracetam is noteworthy. Levetiracetam is rapidly and almost completely absorbed after oral administration, food does not reduce the extent of absorption, protein binding is negligible (<10%), the volume of distribution approximates the volume of intracellular and extracellular water, and elimination is not dependent on the cytochrome P-450 system. About 66% of a dose is excreted renally as unchanged drug. Another 24% undergoes enzymatic hydrolysis. The plasma half-life of levetiracetam is 6-8 hours, longer in elderly persons and persons with renal impairment. Levetiracetam displays linear pharmacokinetics. Pharmacokinetic interactions are considered unlikely.
In three randomized, placebo-controlled studies involving adults with refractory partial onset seizures, the addition of levetiracetam to a stable antiepileptic regimen reduced the frequency of partial seizures. Dosages of 1000, 2000, and 3000 mg/day were shown to be effective. The drug was studied for twice-daily administration.
Adverse effects of levetiracetam include somnolence, asthenia, and dizziness.
The recommended starting dosage of levetiracetam is 500 mg twice daily. The maximum recommended daily dosage is 3000 mg. Patients with renal impairment should receive reduced dosages.
Keppra is supplied as 250-, 500-, and 750-mg tablets in bottles of 100 and 500 and unit dose packages of 100.