Cannabinoids, cannabis, and cannabis-based medicine for pain management: a systematic review of randomised controlled trials

Abstract

Cannabinoids, cannabis, and cannabis-based medicines (CBMs) are increasingly used to manage pain, with limited understanding of their efficacy and safety. We summarised efficacy and adverse events (AEs) of these types of drugs for treating pain using randomised controlled trials: in people of any age, with any type of pain, and for any treatment duration. Primary outcomes were 30% and 50% reduction in pain intensity, and AEs. We assessed risk of bias of included studies, and the overall quality of evidence using GRADE. Studies of <7 and >7 days treatment duration were analysed separately. We included 36 studies (7217 participants) delivering cannabinoids (8 studies), cannabis (6 studies), and CBM (22 studies); all had high and/or uncertain risk of bias. Evidence of benefit was found for cannabis <7 days (risk difference 0.33, 95% confidence interval 0.20-0.46; 2 trials, 231 patients, very low-quality evidence) and nabiximols >7 days (risk difference 0.06, 95% confidence interval 0.01-0.12; 6 trials, 1484 patients, very low-quality evidence). No other beneficial effects were found for other types of cannabinoids, cannabis, or CBM in our primary analyses; 81% of subgroup analyses were negative. Cannabis, nabiximols, and delta-9-tetrahydrocannabinol had more AEs than control. Studies in this field have unclear or high risk of bias, and outcomes had GRADE rating of low- or very low-quality evidence. We have little confidence in the estimates of effect. The evidence neither supports nor refutes claims of efficacy and safety for cannabinoids, cannabis, or CBM in the management of pain.

Medicinal cannabis use in palliative care

“…A more recent review pointed to the low quality of many studies and could not support nor refute claims of benefit. 32 This, along with the aforementioned reviews, illustrates the problem that different systematic reviews use different methodologies and provide disparate results. Others have reviewed the quality of systematic reviews and call for standardisation of reporting before any conclusion can be drawn as to the benefit of cannabis in non-malignant pain.…”

The Effect of Cannabis-Based Medicine on Neuropathic Pain and Spasticity in Patients with Multiple Sclerosis and Spinal Cord Injury: Study Protocol of a National Multicenter Double-Blinded, Placebo-Controlled Trial

“…Only a few studies found a positive effect of CBM on neuropathic pain [40,41], but most studies investigating nabiximols report negative outcomes [10]. Several reviews and meta-reviews conducted on the topic of CBM and NP all conclude that there is no or very limited effect of CBM [13,[42][43][44][45]. The most recent recommendation (2021) from 'The International Association for the Study of Pain' (IASP) does not endorse the use of cannabis and cannabinoids for treating pain due to lack of high-quality clinical evidence [46].…”

Lack of efficacy of cannabidiol for relieving back pain: time to re‐set expectations?

“…A recent systematic review concluded that there is insufficient evidence to support or oppose the use of cannabinoids for treating pain 3 . This followed an Australian systematic review of cannabinoids for treating chronic non‐cancer pain 4 which found that the number needed to treat for 30% pain reduction was 24 and the number needed to harm was six.…”