The new 2018 guideline, published in the official journal of the College of Family Physicians of Canada, suggests that clinicians could consider medical cannabinoids only for refractory neuropathic pain and refractory pain in palliative care, chemotherapy-induced nausea and vomiting, and spasticity in multiple sclerosis and spinal cord injury after reasonable trials of standard therapies have failed.
The Canadian Pain Society has advanced cannabinoid therapy from a fourth-line (2007) to the third-line (2014) recommendation, citing the following evidence:
- Since 2006, seven high quality studies investigated cannabinoid therapy in neuropathic pain, and all but one of these studies had positive results.
- Mucosal spray of 50/50 mixture of THC/CBD provided significant pain relief for patients with multiple sclerosis.
- One trial found that nabilone was effective for pain relief in patients with painful diabetic neuropathy, with improved sleep and overall quality of life.
- There is increasing evidence of the benefits of cannabinoid therapy in managing neuropathic pain: overall NNT of 3.4.