[{"from": "human", "value": "Please give me some details about this molecule. [C][=C][C][Branch1][Branch2][C][C][C][=Branch1][C][=O][O][N]"}, {"from": "gpt", "value": "The molecule is an analog of gamma-aminobutyric acid ([GABA]), the main inhibitory neurotransmitter in the central nervous system, used in the treatment of refractory seizures and infantile spasms. It irreversibly inhibits the enzyme responsible for GABA metabolism, thereby increasing levels of circulating GABA. Although administered as a racemic mixture, only the S(+) enantiomer is pharmacologically active.  It was first introduced as an antiepileptic agent in the United Kingdom in 1989 and was used extensively until 1997, when an association with vision loss became apparent. Its use is now generally reserved for patients who have failed alternative therapies, and its US approval by the FDA in 2009 mandated the creation of a drug registry to monitor patients for visual deficits."}]