Metabolism of Designer Drugs of Abuse: An Updated Review

This paper reviews the metabolism of new designer drugs of abuse that have emerged on the black market during the last years and is an update of a review published in 2005. The presented review contains data concerning the so-called 2C compounds (phenethylamine type) such as 4-bromo-2,5-dimethoxy-beta-phenethylamine (2C-B), 4-iodo-2,5-dimethoxy-beta-phenethylamine (2C-I), 2,5- dimethoxy-4-methyl-beta-phenethylamine (2C-D), 4-ethyl-2,5-dimethoxy-beta-phenethylamine (2C-E), 4-ethylthio-2,5-dimethoxy-beta-phenethylamine (2C-T-2), and 2,5-dimethoxy-4-propylthio-beta-phenethylamine (2C-T-7), beta-keto designer drugs such as 2- methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (butylone, bk-MBDB), 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1- one (ethylone, bk-MDEA), 2-methylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (methylone, bk-MDMA), and 2-methylamino-1- p-tolylpropane-1-one (mephedrone, 4-methyl-methcathinone), pyrrolidinophenones such as 4-methyl-pyrrolidinobutyrophenone (MPBP) and alpha-pyrrolidinovalerophenone (PVP), phencyclidine-derived drugs such as N-(1-phenylcyclohexyl)-propanamine (PCPr), N-(1- phenyl-cyclohexyl)-2-ethoxyethanamine (PCEEA), N-(1-phenylcyclohexyl)-3-methoxypropanamine (PCMPA), and N-(1-phenylcyclohexyl)- 2-methoxyethanamine (PCMEA), tryptamines such as 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), and finally alpha- methylfentanyl (alpha-MF) and 3-methylfentanyl (3-MF). Papers have been considered and reviewed on the identification of in vivo or in vitro human or animal metabolites and the cytochrome P450 or monoamineoxidase isoenzyme-dependent metabolism. Keywords: Designer drugs, phenethylamines, beta-keto amphetamines, pyrrolidinophenones, phencyclidines, tryptamines, fentanyls, cytochrome P450, monoamineoxidase