Smoking marijuana modestly reduced pain and other symptoms of chronic neuropathic pain, results of a small randomized, placebo-controlled trial showed. The most potent dose used reduced average daily pain scores by 0.7 points on an 11-point scale (5.4 versus 6.1 with placebo, 95% confidence interval for difference 0.02 to 1.4), according to Mark A. Ware, MBBS, of McGill University in Montreal, and colleagues.
Those who smoked weed with 9.4% of the active ingredient tetrahydrocannabinol THC) also reported sleeping better, the researchers reported online in CMAJ.These results are important in light of the fact that patients who hear about pain relief from ongoing publicity about medical marijuana have had only a "trickle" of evidence to prove it, explained Henry J. McQuay, DM, of Oxford University, in an accompanying editorial.
"If medical cannabis is not available where a patient lives, then obtaining it will take the patient outside of the law, often for the first time in his or her life," he wrote. "Good evidence would at least buttress that decision."
These quality results along with three other trials of smoked cannabis for neuropathic pain do support an analgesic effect that, "though not great, may be of use to some patients," McQuay concluded.
This study does offer hope since few drugs have proven effective in these patients, commented Steven P. Cohen, MD, who as director of pain research at Walter Reed Army Medical Center in Washington, D.C., sees chronic pain in most of his patients with major war injuries.
