As of 2003, vigabatrin is approved in Mexico for the treatment of epilepsy that is not satisfactorily controlled by conventional therapy (adjunctive or monotherapy) or in recently diagnosed patients who have not tried other agents (monotherapy).
On August 21, 2009, Lundbeck announced that the U.S. Food and Drug Administration had granted two New Drug Application approvals for vigabatrin. The drug is indicated as monotherapy for pediatric patients one month to two years of age with infantile spasms for whom the potential benefits outweigh the potential risk of vision loss, and as adjunctive (add-on) therapy for adult patients with refractory complex partial seizures (CPS) who have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss.
Some patients develop psychosis during the course of vigabatrin therapy, which is more common in adults than in children. This can happen even in patients with no prior history of psychosis. Other rare CNS side effects include anxiety, emotional lability, irritability, tremor, abnormal gait, and speech disorder.
Abdominal pain (1.6%), constipation (1.4%), vomiting (1.4%), and nausea (1.4%). Dyspepsia and increased appetite occurred in less than 1% of subjects in clinical trials.
Body as a whole
Fatigue (9.2%), weight gain (5.0%), asthenia (1.1%).
A teratology study conducted in rabbits found that a dose of 150 mg/kg/day caused cleft palate in 2% of pups and a dose of 200 mg/kg/day caused it in 9%. This may be due to a decrease in methionine levels, according to a study published in March 2001. In 2005, a study conducted at the University of Catania was published stating that rats whose mothers had consumed 250–1000 mg/kg/day had poorer performance in the water maze and open-field tasks, rats in the 750-mg group were underweight at birth and did not catch up to the control group, and rats in the 1000 mg group did not survive pregnancy.
There is no controlled teratology data in humans to date.
In 2003, vigabatrin was shown by Frisén and Malmgren to cause irreversible diffuse atrophy of the retinalnerve fiber layer in a retrospective study of 25 patients. This has the most effect on the outer area (as opposed to the macular, or central area) of the retina.
Visual field defects had been reported as early as 1997 by Tom Eke and others, in the UK. Some authors, including Comaish et al. believe that visual field loss and electrophysiological changes may be demonstrable in up to 50% of Vigabatrin users.
The retinal toxicity of vigabatrin can be attributed to a taurine depletion.
Due to safety issues, the Vigabatrin REMS Program is required by the FDA to ensure informed decisions before initiating and to ensure appropriate use of this drug. 
In 1984, Drs Rimmer and Richens at the University of Wales reported that administering vigabatrin with phenytoin lowered the serum phenytoin concentration in patients with treatment-resistant epilepsy. Five years later, the same two scientists reported a fall in concentration of phenytoin of 23% within five weeks in a paper describing their failed attempt at elucidating the mechanism behind this interaction.
Crystal Structure (pdb:1OHW) showing vigabatrin binding to specific residues in the active site of GABA-AT, based off experiments by Storici et al.
With most drugs, elimination half-life is a useful predictor of dosing schedules and the time needed to reach steady state concentrations. In the case of vigabatrin, however, it has been found that the half-life of biologic activity is far longer than the elimination half-life.
For vigabatrin, there is no range of target concentrations because researchers found no difference between the serum concentration levels of responders and those of non-responders. Instead, the duration of action is believed to be more a function of the GABA-T resynthesis rate; levels of GABA-T do not usually return to their normal state until six days after stopping the medication.
Vigabatrin was developed in the 1980s with the specific goal of increasing GABA concentrations in the brain in order to stop an epileptic seizure. To do this, the drug was designed to irreversibly inhibit the GABA transaminase, which degrades the GABA substrate. Although the drug was approved for treatment in the United Kingdom in 1989, the authorized use of Vigabatrin by US Food and Drug Administration was delayed twice in the United States before 2009. It was delayed in 1983 because animal trials produced intramyelinic edema, however, the effects were not apparent in human trials so the drug design continued. In 1997, the trials were temporarily suspended because it was linked to peripheral visual field defects in humans.
Society and culture
Vigabatrin is sold as Sabril in Canada, Mexico,
and the United Kingdom. The brand name in Denmark is Sabrilex. Sabril was approved in the United States on August 21, 2009 and is currently marketed in the U.S. by Lundbeck Inc., which acquired Ovation Pharmaceuticals, the U.S. sponsor in March 2009.
On January 16, 2019, the FDA approved the first generic version of Sabril (vigabatrin) in the United States.
^Chiaretti A, Castorina M, Tortorolo L, Piastra M, Polidori G (1994). "[Acute psychosis and vigabatrin in childhood]". La Pediatria Medica e Chirurgica : Medical and Surgical Pediatrics. 16 (5): 489–90. [Article in Italian] PMID7885961
^Abdulrazzaq YM, Padmanabhan R, Bastaki SM, Ibrahim A, Bener A (2001). "Placental transfer of vigabatrin (gamma-vinyl GABA) and its effect on concentration of amino acids in the embryo of TO mice". Teratology. 63 (3): 127–33. doi:10.1002/tera.1023. PMID11283969.
^Sanchez-Alcaraz, Agustín; Quintana MB; Lopez E; Rodriguez I; Llopis P (2002). "Effect of vigabatrin on the pharmacokinetics of carbamazepine". Journal of Clinical Pharmacology and Therapeutics. 27 (6): 427–30. doi:10.1046/j.1365-2710.2002.00441.x. PMID12472982.
^Storici Paola; De Biase D; Bossa F; Bruno S; Mozzarelli A; Peneff C; Silverman R; Schirmer T. (2003). "Structures of γ-Aminobutyric Acid (GABA) Aminotransferase, a Pyridoxal 5'-Phosphate, and [2Fe-2S] Cluster-containing Enzyme, Complexed with γ-Ethynyl-GABA and with the Antiepilepsy Drug Vigabatrin". The Journal of Biochemistry. 279 (1): 363–73. doi:10.1074/jbc.M305884200. PMID14534310.
^Lindberger M, Luhr O, Johannessen SI, Larsson S, Tomson T (2003). "Serum concentrations and effects of gabapentin and vigabatrin: observations from a dose titration study". Therapeutic Drug Monitoring. 25 (4): 457–62. doi:10.1097/00007691-200308000-00007. PMID12883229.