Analgesic properties of THC and its synthetic derivatives

Cannabis has been used for thousands of years for the treatment of pain res ulting from a wide range of disorders. Although clinical evaluations of Can nabis and its psychoactive constituent THC: have not led to a general conse nsus regarding their analgesic effectiveness, THC and other synthetic canna binoid analogs elicit antinociception in a variety of pain tests in laborat ory animals. These antinociceptive effects are mediated through cannabinoid receptors in the central nervous system which, in turn, modulate the perce ption of painful stimuli. The endogenous ligand, arachinodyl-ethanolamine ( anandamide), is also an effective antinociceptive agent in experimental mod els. The extent to which the endogenous cannabinoid system is involved in t he modulation of pain is currently unknown. Coadministration of opioids and THC by the intrathecal route produces an additive antalgic effect. Recent work indicates that coadministration of opioids and cannabinoids produces a t least an additive effect. The possibility exists that the analgesic effec ts can be optimized and untoward effects be minimized if agents from these two classes of drugs were coadministered for the treatment of painful condi tions.