Lack of evidence for cannabis in adults with chronic neuropathic pain

Bottom Line:

There was no high-quality evidence for the efficacy of any CBM (herbal cannabis, plant-derived tetrahydrocannabinol (THC) (dronabinol), synthetic THC (nabilone), plant-derived THC/cannabidiol (CBD) com bination) in any condition with chronic neuropathic pain. The studies were two to 26 weeks long and compared an oromucosal spray with a plant-derived combination of THC and CBD (10 studies), a synthetic cannabinoid mimicking THC (nabilone) (two studies), inhaled herbal cannabis (two studies) and plant-derived THC (dronabinol) (two studies) against placebo (15 studies) and an analgesic (dihydrocodeine) (one study). Herbal cannabis was not different from placebo in reducing pain and the number of people who dropped out due to side effects. Some adverse events (particularly somnolence or sedation, confusion, psychosis) might limit the clinical usefulness of cannabis-based medicines.