Cannabinor (PRS-211,375) is a drug which acts as a potent and selective cannabinoid CB<sub>2</sub> receptor agonist. It is classed as a "nonclassical" cannabinoid with a chemical structure similar to that of cannabidiol. It has a CB<sub>2</sub> affinity of 17.4 nM vs 5,585 nM at CB<sub>1</sub>, giving it over 300ÃÂ selectivity for CB<sub>2</sub>. It showed analgesic effects in animal studies especially in models of neuropathic pain, but failed in Phase IIb human clinical trials due to lack of efficacy.