Therapeutic Use of Synthetic Cannabinoids: Still an Open Issue?

Cannabis sativa has a long history of use for medical purposes despite marijuana's addictive potential. The discovery of the endogenous cannabinoid system as a neuromodulatory system composed of receptors, endogenous ligands (endocannabinoids), and enzymes responsible for their synthesis and degradation, together with recent advancements in the elucidation of cannabinoid pharmacology, has renewed interest in medicines acting on the endocannabinoid system. Synthetic cannabinoid agonists have been developed and used for treatment of different human pathologic conditions, and promising potent cannabinoid antagonists are currently under clinical evaluation. During the last decade, new generations of synthetic cannabinoids appeared on the global drug market, proposed as marijuana-like compounds and sold as herbal mixture also known as spice drugs or legal highs. Because activation of cannabinoid receptors may induce central and peripheral beneficial effects, the newest synthetic cannabinoids having full agonistic activity and high potency at cannabinoid type 1 and type 2 receptors might have therapeutic potential too. However, case reports of acute and fatal intoxications are accumulating and revealing that this is not the case because adverse effects of the latest generation of synthetic cannabinoids far exceed the desired ones.