New psychoactive substances as adulterants of controlled drugs. A worrying phenomenon?

The use of new psychoactive substances (NPS) as adulterants has received little attention in the literature. In this paper, results from Energy Control's drug checking service documenting the use of NPS as adulterants of controlled drugs are presented, and some reflections about possible explanations for this new phenomenon, potential risks for users, and challenges that it poses are discussed. From 2009 to 2012, 24 NPS belonging to several chemical classes such as phenethylamines, substituted cathinones, tryptamines, and methoxetamine were identified in 173 samples believed to be MDMA, amphetamine, ketamine, cocaine, mescaline, or methamphetamine. The NPS adulterant most frequently observed was 2-(4-bromo-2,5-dimethoxyphenyl)ethanamine (2C-B) followed by 1-(4-fluorophenyl)propan-2-amine (4-FA). Sixty-nine different combinations of substances were detected: 20 involving a controlled drug combined with an NPS, and 49 involving one or more NPS that substituted the controlled drug. As these combinations could pose substantial risks to users, the need to improve knowledge about toxicity associated with these combinations, and the danger of these substances being incorporated into the products of illegal markets, are highlighted. Drug checking services and the European Union's early-warning system operated by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and Europol can play an important role in reducing the harm associated with this phenomenon.