Product Information
Registration Status: ActiveSABRIL TABLET 500mg is approved to be sold in Singapore with effective from 1994-09-12. It is marketed by SANOFI-AVENTIS SINGAPORE PTE LTD, with the registration number of SIN07955P.
This product contains Vigabatrin 500mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by Patheon France in FRANCE.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Description
An analogue of gamma-aminobutyric acid, vigabatrin is an irreversible inhibitor of 4-aminobutyrate transaminase, the enzyme responsible for the catabolism of gamma-aminobutyric acid. (From Martindale The Extra Pharmacopoeia, 31st ed). Off-label uses include treatment of cocaine dependence.
Indication
For use as an adjunct in treatment resistant epilepsy, refractory complex partial seizures, and secondary generalized seizures. It is also used as monotherapy in infantile spasms in West syndrome.
Mechanism of Action
Vigabatrin increases brain concentrations of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the CNS, by irreversibly inhibiting enzymes that catabolize GABA (gamma-aminobutyric acid transaminase, GABA-T). Duration of action is determined by rate of GABA-T re-synthesis. Vigabatrin may also work by suppressing repetitive neuronal firing through inhibition of voltage-sensitive sodium channels. Although administered as a racemic mixture, only the S(+) enantiomer is pharmacologically active.
Pharmacokinetics
- Absorption
- Rapidly absorbed following oral administration, absorption is comparable between neonates, infants, and children. Cmax, 50 mg/kg dose, neonates= 14 mg/L; Tmax, 50 mg/kg dose, neonates = 2.1 hours; However, extent of absorption is higher and elimination half life is longer in neonates compared to children and infants. This is because neonates have reduced renal function compared to the aforementioned population groups. AUC, 50 mg/kg dose, neonates = 142.6 ± 44.0 mg/L/hr; Food may slightly decrease the rate (Cmax decreased by 33%, Tmax increased to 2 hours), but not the extent of absorption. Furthermore, vigabatrin does not cross the blood-brain-barrier well, thus high doses are needed.
- Distribution
- 1.1 L/kg
- Metabolism
- Almost no metabolic transformation. Does not induce the hepatic cytochrome P450 system.
- Elimination
Clearance
Infants = 2.4 ± 0.8 L/h; Children = 5.7 ± 2.5 L/h
Toxicity
LD50, oral, rat: 3000 mg/kg; Visual field defects may occur following cumulative doses in excess of 2 kg.
Active Ingredient/Synonyms
4-Amino-5-hexenoic acid | Gamma vinyl GABA | gamma-Vinyl GABA | gamma-Vinyl-gamma-aminobutyric acid | GVG | Vigabatrin | Vigabatrina | Vigabatrine | Vigabatrinum | Vinyl gamma-aminobutyric acid | Vigabatrin |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.