in canada, ghb has been a schedule i controlled substance since 6 november 2012 (the same schedule that contains heroin and cocaine). prior to that date, it was a schedule iii controlled substance (the same schedule that contains amphetamines and lsd). in new zealand and australia, ghb, 1,4-b, and gbl are all class b illegal drugs, along with any possible esters, ethers, and aldehydes. gaba itself is also listed as an illegal drug in these jurisdictions, which seems unusual given its failure to cross the blood–brain barrier, but there was a perception among legislators that all known analogues should be covered as far as this was possible. attempts to circumvent the illegal status of ghb have led to the sale of derivatives such as 4-methyl-ghb (γ-hydroxyvaleric acid, ghv) and its prodrug form γ-valerolactone (gvl), but these are also covered under the law by virtue of their being "substantially similar" to ghb or gbl, so importation, sale, possession and use of these compounds is also considered to be illegal. in chile, ghb is a controlled drug under the law ley de substancias psicotrópicas y estupefacientes (psychotropic substances and narcotics). in norway and in switzerland, ghb is considered a narcotic and is only available by prescription under the trade name xyrem (union chimique belge s.a.). sodium oxybate is also used therapeutically in italy under the brand name alcover for treatment of alcohol withdrawal and dependence.