Objective: To establish whether cannabis is an effective and safe analgesic in chronic painful conditions.
Background: The medical applications of Cannabis have long been a focus of public and scientific interest. Cannabinoids are the active compounds extracted from the Cannabis Sativa plant. Recently there has been renewed interest in cannabinoids for medicinal purposes. The discovery of cannabinoid CB1/CB2 receptors and endogenous ligands, has shed new light on the therapeutic potential of cannabinoids in the management of pain.
Methods: A systematic literature search was done using different search strategies in MEDLINE (1966-2006) and the Cochrane Library. The most recent search was done January 2006, using different combinations of the following MESH headings: CANNABINOIDS, CANNABIS, PAIN, CENTRAL PAIN, NEUROPATHIC PAIN, CHRONIC PAIN, CANCER PAIN.We systematically sought randomised controlled trials and reviews.All retrieved reports were checked for inclusion and exclusion criteria by the two authors.
Material: From twenty relevant papers, 12 were excluded and 8 included according to the criteria. The included material contained 3 systematic reviews and 5 RCTs.
Results: The review articles concluded that cannabinoids (primarily THC) were no more effective than codeine in controlling pain, and the psychotropic side effects limited their use. New formulas of cannabinoids are showing potential with less side effects. The effects were shown to be significantly better than placebo, but need to be compared to existing analgesics to prove their place in palliative medicine.
Conclutions: Before cannabinoids can be considered as a safe treatment option in conditions with chronic pain, further valid randomised controlled studies are required.