Cannabis-based medicines and medical cannabis for patients with neuropathic pain and other pain disorders: Nationwide register-based pharmacoepidemiologic comparison with propensity score matched controls

Background: Neuropathic pain and other pain disorders have received attention as potential indications for use of cannabis-based medicines or medical cannabis (CBM/MC). Evidence regarding the efficacy and safety of CBM/MC for pain disorders is, however, insufficient. Denmark introduced a pilot program of medical cannabis in January 2018. We aimed to evaluate efficacy, safety, and non-specific effects of CBM/MC used under the pilot program compared with controls.

Methods: We conducted a nationwide register-based cohort study in Denmark, identifying all individuals redeeming at least one prescription for CBM/MC for either neuropathic pain (n=1,817) or other and unspecified pain disorders (n=924), and to match one control to each case using propensity score matching.

Results: Among both patient groups, users of THC used more opioids during follow-up than controls. Among patients with neuropathic pain, however, users of either CBD, THC, or combined CBD+THC used less gabapentin than controls. Users of all three classes of CBM/MC were hospitalized fewer days than controls among neuropathic-pain patients but not among patients with other or unspecified pain disorders.

Conclusions: CBM/MC were generally safe and even displayed some positive effects among patients with neuropathic pain. We conclude that CBM/MC are safe and possibly efficacious for patients with neuropathic pain but not patients with other pain disorders.