 Butorphanol can also be derived from thebaine.Thebaine is controlled under international law, is listed as a Class A drug under the Misuse of Drugs Act 1971 in the United Kingdom, is controlled as an analog of a Schedule II drug per the Analog Act in the United States, and is controlled with its derivatives and salts, as a Schedule I substance of the Controlled Drugs and Substances Act in Canada.The 2013 US Drug Enforcement Administration (DEA) aggregate manufacturing quota for thebaine (ACSCN 9333) was unchanged from the previous year at 145 metric tons.