Cannabinoids may improve sleep quality, pain intensity, and patient global impression of change (PGIC) among patients with chronic neuropathic pain, according to results of a systematic review and meta-analysis published in Regional Anesthesia & Pain Medicine.
A team of Canadian investigators searched publication databases for studies evaluating cannabinoid use among patients with neuropathic pain published between 1995 and 2021. A cutoff of tetrahydrocannabinol (THC) 100 mg was used to identify high- and low-dose treatments. Their search yielded 8 studies conducted in Canada and Europe that included data from 1051 patients.
The mean age of the study population was 51.1 years, and interventions included THC-cannabidiol (CBD) preparations with a THC dosage ranging from 1 to 130 mg/d and a CBD dosage ranging from 2.5 to 120 mg/d. Most studies allowed for concomitant use of other medications for managing neuropathic pain. Opioids were used most frequently, and their use ranged from 14% to 74% of study participants across all trials.
In the meta-analysis, treatment with cannabinoids was associated with significantly improved sleep quality (standardized mean difference [SMD], 0.4; 95% CI, 0.19-0.61; I2, 55.26%; P =.002), numeric rating scale (NRS) scores for pain (SMD, -0.44; 95% CI, -0.69 to -0.19; I2, 82.49%; P =.003), and PGIC scores (odds ratio [OR], 4.2; 95% CI, 1.37-12.87; P =.031) compared with placebo.
Use of cannabinoids was also associated with more dizziness (OR, 3.8; 95% CI, 2.52-5.73; I2, 6.32%; P <.001), daytime somnolence (OR, 2.23; 95% CI, 1.32-3.74; I2, 8.23%; P =.007), and nausea (OR, 1.66; 95% CI, 1.22-2.27; I2, 0.00%; P =.005) compared with placebo.
In the mediator analysis, dosage significantly moderated the effect on sleep quality favoring high-dose treatment (P =.038) and risk of bias significantly moderated the effect on nausea (P <.001).
The results from the leave-one-out sensitivity analysis were broadly consistent with the main analysis.
This study may have been biased by pooling data from patients with various neuropathic pain etiologies.
Study authors concluded, “Cannabinoids are useful agents for treating neuropathic pain as evidenced by significant improvement in sleep quality, pain, and PGIC. However, these benefits were noted at the expense of increased daytime somnolence, dizziness, and nausea. With the advent of new agents and more refined cannabis formulations, further research is needed to comprehensively explore treatment effectiveness.”
McParland AL, Bhatia A, Matelski J, et al. Evaluating the impact of cannabinoids on sleep health and pain in patients with chronic neuropathic pain: a systematic review and meta-analysis of randomized controlled trials. Reg Anesth Pain Med. Published online December 5, 2022. doi:10.1136/rapm-2021-103431