Vigabatrin (γ-vinyl-GABA) an AED is a structural analogue of GABA, but does not bind to GABA receptors.
UK-SmPC: (1) monotherapy in the treatment of infantile spasms and (2) treatment in combination with other anti-epileptic drugs for patients with resistant partial epilepsy with or without secondary generalisation, where all other appropriate drug combinations have proved inadequate or have not been tolerated.
FDA-PI: Vigabatrin (Sabril®) was approved on 21 August 2009 by the US FDA for treatment of infantile spasms in children, and uncontrolled complex partial seizures in adults.
Adults: start treatment with 500 mg/day and titrate in increments of 500 mg/day every week. Typical adult maintenance dose is 1000–3000 mg/day given in two equally divided doses.Because the excretion is mainly renal, the dose should be reduced in patients with renal insufficiency and creatinine clearance
Children with infantile spasms: start treatment with 50 mg/kg/day and adjust according to the response over 7 days, up to a total of 150–200 mg/kg/day.
Dosing: despite its short half-life (5–7 hours), vigabatrin may be given once or twice daily, because inhibition of GABA-T results in a relatively long duration of action, and GABA levels in the CSF can remain elevated for up to 120 hours after a single oral dose.
TDM: unnecessary; useful only to check compliance.18,19
Reference range: 6–278 μmol/l, which is irrelevant in clinical practice.