Pharmacology of cannabinoids: applications for pain treatment?

Objective: To present the cannabinoid system together with recent findings on the pharmacology of these compounds in the treatment of pain. Data sources: Search through Medline((R)) database of articles published in French and English since 1966. Also use of other publications such as books on cannabis. Study selection: All the relevant documents within the theme of this review were used. Data extraction: All the data linked to the present topic were searched. Data synthesis: Recent advances have dramatically increased our understanding of cannabinoid pharmacology. The psychoactive constituents of Cannabis sativa have been isolated, synthetic cannabinoids described and an endocannabinoid system identified, together with its component receptors and ligands. Strong laboratory evidence now underwrites anecdotal claims of cannabinoid analgesia in inflammatory and neuropathic pain. Sites of analgesic action have been identified in brain, spinal cord and the periphery, with the latter two presenting attractive targets for divorcing the analgesic and psychotrophic effects of cannabinoids. Clinical trials are now required, but are hindered by a paucity of cannabinoids of suitable bioavailability and therapeutic ratio. Conclusion: The cannabinoid system is a major target in the treatment of pain and its therapeutic potential should be assessed in the near future by the performance of new clinical trials. (C) 2002 Editions scientifiques et medicales Elsevier SAS.