Acute Pharmacological Effects and Oral Fluid Biomarkers of the Synthetic Cannabinoid UR-144 and THC in Recreational Users

UR-144 is a synthetic cannabinoid found in herbal incenses for recreational use as a substitute of cannabis. It is a cannabinoid receptor agonist with effects on the central nervous system similar to those of THC. Several cases of intoxication involving UR-144 consumption have been reported. An observational study was carried out to assess UR-144 acute pharmacological effects in comparison with cannabis measuring biomarkers of disposition in oral fluid. Both UR-144 and THC increased blood pressure and heart rate. THC induced stimulant-like and high effects significantly more than those of UR-144 and the two parent drugs could be measured in oral fluid as biomarkers of consumption within 3 h following smoking of the substance. Synthetic cannabinoids (SCs) are one of the most frequent classes of new psychoactive substances monitored by the EU Early Warning System and World Health Organization. UR-144 is a SC with a relative low affinity for the CB1 receptor with respect to that for the CB2 receptor. As with other cannabinoid receptor agonists, it has been monitored by the EU Early Warning System since 2012 for severe adverse effects on consumers. Since data for UR-144 human pharmacology are very limited, an observational study was carried out to evaluate its acute pharmacological effects following its administration using a cannabis joint as term of comparison. Disposition of UR-144 and delta-9-tetrahydrocannibinol (THC) was investigated in oral fluid. Sixteen volunteers smoked a joint prepared with tobacco and 1 or 1.5 mg dose of UR-144 (n = 8) or cannabis flowering tops containing 10 or 20 mg THC (n = 8). Physiological variables including systolic and diastolic blood pressure, heart rate and cutaneous temperature were measured. A set of Visual Analog Scales (VAS), the Addiction Research Centre Inventory (ARCI)-49-item short form version and the Evaluation of the Subjective Effects of Substances with Abuse Potential (VESSPA-SSE) were administered to evaluate subjecti