Ketamine: From Prescription Anaesthetic to a New Psychoactive Substance.

Discovered in the United States of America (USA) in the 1960s, ketamine was introduced as an anaesthetic drug to specifically replace phencyclidine. Briefly, the substance moved from the medical world to recreational users, since it was discovered that intense psychedelic experiences were obtained with dosages lower than those prescribed for anesthesia. At the end of the 90's, it was circulated in London nightclubs as a drug itself and as counterfeit 3,4-methylenedioxymethamphetamine tablets. In 1997, the Drug Enforcement Administration (DEA) alerted the United States (US) government about the increasing diffusion of ketamine in American 'clubs', and in 1999, the substance was added to Schedule III of drugs controlled by federal authorities. In 2002, ketamine epidemics moved to Europe, and the European Monitoring Centre for Drugs and Drug Addiction carried out a risk assessment monitoring of the phenomenon. An estimated ninety-nine percent of all global ketamine seizures occurred in Asia. Its growing popularity is due to the fact that this new psychoactive substance is cheaper than other stimulants, such as MDMA. Moreover, the amount used for recreational purposes does not cause respiratory depression and its legal use as a drug makes it widely available for a diversion towards illicit markets. Nevertheless, acute intoxication and several deaths have been related to exclusive ketamine use both in Europe and internationally. Since 2015, there has been an increasing rise in the illicit ketamine market, and currently, the drug is being used with unprecedented peaks and a consequent significant increase in seizures and clinical cases worldwide.