Changes in the prevalence of synthetic cannabinoids and cathinone derivatives in Japan until early 2012

The changes in the prevalence of designer drugs and their legal status in Japan were investigated on the basis of the analyses of 686 different products containing synthetic cannabinoids and/or cathinone derivatives obtained from 2009 to February 2012. In the early stages of distribution of herbal-type products containing synthetic cannabinoids, cyclohexylphenols and naphthoylindoles were mostly found in the products. In November 2009, however, cannabicyclohexanol, CP-47,497 and JWH-018 were controlled as “designated substances” under the Pharmaceutical Affairs Law in Japan, and the cyclohexylphenols have since disappeared from the illegal drug market and been replaced by various analogs of the naphthoylindoles, phenylacetylindoles and benzoylindoles. These compounds, which have high affinities for the cannabinoid CB₁ receptor, have become very popular, and the number of emergency hospitalizations associated with their use has dramatically increased from 2011. Other synthetic compounds with different structures and pharmacological effects, such as cathinone derivatives, have been detected together with the synthetic cannabinoids in herbal-type products since 2011. Moreover, many new types of synthetic cannabinoids, different from the four typical structures described, have also begun to appear since 2011. In addition to the synthetic cannabinoids, liquid or powdery-type products containing cathinone derivatives have been widely distributed recently. In 2009, the most popular cathinone derivative was 4-methylmethcathinone. After this compound was controlled as a designated substance in November 2009, cathinone derivatives, which have a pyrrolidine structure at the nitrogen atom and a 3,4-methylenedioxy structure, or analogs of 4-methylmethcathinone, became popular. In the present analysis, tryptamines were also detected in 31 % of the products containing cathinone derivatives. Local anesthetics such as procaine, lidocaine, benzocaine and dimethocaine were also frequently detected. In total, we identified at least 35 synthetic cannabinoids and 22 cathinone derivatives during this survey.