Felbamate

Actions

• Blocks voltage-dependent Na+ channels at high firing frequencies.
• Modulates NMDA receptor negatively and GABA receptor positively.

Metabolism

Hepatic

Enzyme induction

• CYP3A4

Enzyme inhibition

• CYP2C19

Elimination

Renal 30%

Therapeutic serum concentration range

40-100 μg/ml

Half-life

20–23 hours

Plasma protein binding

20-36%

Important side-effects

Aplastic anemia

Hepatic failure

Suicidal behavior and ideation

Spectrum

Focal seizures with or without generalization.

Focal or generalized seizures associated with Lennox-Gastaut syndrome.

Dosing recommendation

Start with 600-1200 mg/day divided in 2-3 doses.

Increment at weekly intervals by 600-1200 mg/day.

Target dose: 1800–3600 mg/day divided in 2-3 doses.

Renal impairment

In patients with creatinine clearance <30 mg/ml the initial dose should be halved and any dose increases should be done with caution.

Hepatic impairment

Felbamate is not recommended in patients with impaired hepatic function.