The practice of drug of abuse adulteration is changing. Currently, the risk of new adulteration practices involves New Psychoactive Substances (NPS), which can also be used as adulterants. In particular, the phenomenon of adulteration concerns fentanyl and its analogs, substances that can be toxic even if taken in very small quantities. The adulteration that involves NPS is creating a serious threat to the health of drug users, not only because of the pharmacological action but because of the increased toxicity of these new cutting agents.
Keywords: Adulteration; Drug of abuse; New psychoactive substances.