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Medical marijuana safe, slightly reduces MS symptoms

Medicinal cannabinoids were considered safe and demonstrated a limited effectiveness in treating spasticity, pain and bladder dysfunction symptoms in patients with multiple sclerosis, according findings published in JAMA Network Open.

“Cannabinoids have antispastic and analgesic effects; however, their role in the treatment of multiple sclerosis (MS) symptoms is not well defined,” Mari Carmen Torres-Moreno, PhD, from the Universitat Autònoma de Barcelona, Spain, and colleagues wrote.

Torres-Moreno and colleagues performed a systematic review and meta-analysis to determine if medicinal cannabinoids are effective and well tolerated in the treatment of MS. The researchers reviewed 17 randomized, double-blind, placebo-controlled trials that assessed the effects of medicinal cannabinoids administered via oral or oromucosal route on spasticity, pain and/or bladder dysfunction in adult patients with MS (n = 3,161).

Data revealed that medicinal cannabinoids were significantly associated with efficacy regarding subjective spasticity (standardized mean difference = –0.25; 95% CI, –0.38 to –0.13), pain (standardized mean difference = –0.17; 95% CI, –0.31 to –0.03) and bladder dysfunction (standardized mean difference –0.11; 95% CI, –0.22 to –0.0008), compared with placebo.

Patients receiving medicinal cannabinoids had an increased risk for adverse events (rate ratio = 1.72 patient-years; 95% CI, 1.46-2.02) and withdrawals due to adverse events (rate ratio = 2.95 patient-years; 95% CI, 2.14-4.07), compared with placebo. There was no statistically significant difference in serious adverse events between patients receiving medicinal cannabinoids and those receiving placebo.

“Cannabinoids produce a limited and mild reduction of subjective spasticity, pain, and bladder dysfunction in patients with MS, but no changes in objectively measured spasticity. They can be considered safe drugs, as the analysis of serious adverse events did not show statistical significance, although the total number of adverse events is higher than in placebo for the treatment of symptoms in patients with MS,” Torres-Moreno and colleagues concluded.

In an accompanying editorial, Marissa Slaven, MD, and Oren Levine, MD, MSc, both from McMaster University, Ontario, Canada, wrote that the meta-analysis by Torres-Moreno and colleagues was “methodologically sound,” but that does not outweigh the limitation of including “relatively weak” studies.

“In light of uncertainty around clinically meaningful benefit and heterogeneity of the studies and results, [the researchers] appropriately avoid drawing strong conclusions regarding the role for cannabinoids in managing symptoms of MS,” they concluded. “Given the relative safety of these agents, lack of strong evidence of other effective treatment options, and increasing access in some jurisdictions, it may seem appealing to include cannabinoids in the armamentarium of therapies for MS. But carefully conducted, high-quality studies with thought given to the biologic activity of different cannabis components are still required to inform on the benefits of cannabinoids for patients with MS.” – by Alaina Tedesco

Disclosure: The authors report no relevant financial disclosures.