CB₂ cannabinoid receptor agonists: Pain relief without psychoactive effects?

Cannabinoid receptor agonists significantly diminish pain responses in animal models; however, they exhibit only modest analgesic effects in humans. The relative lack of efficacy in man may be because of the dose limitations imposed by psychoactive side effects. Cannbinoid agonists that selectively target CB₂ (peripheral) cannabinoid receptors should be free of psychoactive effects, perhaps allowing for more effective dosing. CB₂ receptor activation inhibits acute, inflammatory and neuropathic pain responses in animal models. In preclinical studies, CB₂ receptor agonists do not produce central nervous system effects. Therefore, they show promise for the treatment of acute and chronic pain without psychoactive effects.