Opioid receptors and legal highs:Salvia divinorumand Kratom
Clinical Toxicology January 1, 2008 Kavita M. Babu, Christopher R. McCurdy, Edward W. Boyer 221 citations
Salvia divinorum and Kratom are unscheduled dietary supplements that activate opioid receptors and produce distinct psychoactive effects. Salvinorin A, from Salvia divinorum, is a highly selective kappa-opioid receptor agonist that causes visual hallucinations and synesthesia. Kratom's main alkaloid, mitragynine, acts as a partial opioid agonist with morphine-like effects, while its minor alkaloid 7-hydroxymitragynine is more potent than morphine. Both Kratom alkaloids activate supraspinal mu- and delta-opioid receptors, which explains their use by chronic narcotics users to ease opioid withdrawal. Despite widespread Internet availability, these substances elude traditional toxicologic monitoring, and the article aims to inform toxicologists and poison control specialists about them.