Cannabinoids for spasticity in patients with multiple sclerosis: A systematic review and meta-analysis.

Background: One of the most disabling symptoms of patients with multiple sclerosis (MS) is spasticity which affects their quality of life. Nowadays, cannabinoids are used for spasticity control in patients with MS, while the efficacy and safety are not clearly understood. So, we designed this systematic review and meta-analysis to assess the efficacy of cannabinoids for controlling MS-related spasticity.

Methods: PubMed, Scopus, EMBASE, Web of Science, and Google Scholar were systematically searched by two independent researchers on 1 May 2023. They also searched gray literature (references of included studies, as well as conference abstracts).

Results: A literature search revealed 6552 records, 95 full-texts were evaluated, and finally, 31 studies remained for systematic review. Among included studies, six randomized trials were included. Nabiximols was the most commonly used medication for controlling MS-related spasticity. Mean Expanded Disability Status Scale ranged between 4.6 and 7. Most studies (17 studies) were done in Italy, followed by Germany (4 studies). The pooled standardized mean difference (SMD) of NRS (Numeric Rating Scale) (after-before) is estimated as -1.41 (95% confidence interval (CI): -1.65, -1.17) (I² = 97%, p < 0.001). The pooled standardized mean difference (SMD) of Ashworth (after-before) is estimated as -0.39 (95% CI: -0.72, -0.06) (I² = 69.9%, p = 0.005).

Conclusion: The results of this systematic review and meta-analysis showed that nabiximols was the most common cannabinoid which was used to control MS-related spasticity, and it was effective in controlling MS-related spasticity (significantly decreased SMD of NRS, and Ashworth after treatment).