New Danish research published in ARD suggest cannabidiol does not provide pain relief in fibromyalgia patients.
Findings from a self-proclaimed “robust” trial for CBD in fibromyalgia still suggests that the treatment comes up short compared to placebo.
Cannabidiol- (CBD) containing products are used by many fibromyalgia patients to help manage their pain despite there being limited evidence supporting its efficacy. The results of a recent single-centre, randomised double-blind trial performed in Denmark adds to the negative pile, reporting daily doses of CBD were not effective at reducing pain in their cohort of fibromyalgia patients.
“Our study did not support [the] analgesic efficacy of treatment with CBD 50mg daily compared to placebo in patients with fibromyalgia,” the researchers wrote in the Annals of the Rheumatic Diseases.
“Furthermore, the study did not show beneficial effects of CBD on other core outcomes such as functional ability, quality of sleep and quality of life in this patient population.”
Researchers recruited 200 adult patients with fibromyalgia (as per the American College of Rheumatology’s diagnostic criteria) who reported an average pain intensity of at least four out of 10 and who had not used cannabis within the previous six month.
Patients with systemic inflammatory rheumatic disorders and patients who were currently being treated with opioids, opioid antagonists or similarly strong analgesics were excluded.
The patients were randomised to receive either 50mg of CBD or placebo via a once daily tablet for 24 weeks on a 1:1 basis. A similar number of patients in each group completed the full course of treatment (83 in the CBD group compared to 86 in the placebo group).
Almost all (94.5%) included patients were female and most patients (61.5%) reported that their chronic pain symptoms had lasted for more than five years. The average age of included participants was 49.9 years.
After 24 weeks of treatment the primary outcome measure – the change in pain intensity from baseline as measured by the 11-point numerical scale of the revised Fibromyalgia Impact Questionnaire (FIQ-R; where 0 represents no pain and 10 represents the worst possible pain) – favoured placebo over CBD.
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Patients in the placebo group reported an average reduction in pain intensity of 1.1 points while patients in the CBD group reported an average reduction of 0.4 points (mean between-groups difference -0.7, 95% confidence interval -1.20 to -0.25).
Furthermore, a greater proportion of patients in the placebo group reported a one-unit improvement in pain (31% versus 17%), a 30% improvement in pain (25% versus 6%) and a 50% improvement in pain (11% versus 2%) as measured by the FIQ-R compared to the CBD group.
When secondary outcomes were considered, patients in the placebo group reported a greater improvement in quality of life compared to the CBD group (mean between-group difference 6.3, as measured by the EuroQol EQ-5D questionnaire), while patients in the CBD group were observed to spend more time resting overnight (mean between-group difference of 22 minutes, measured by a triaxial accelerometer).
“Our findings of no benefits for CBD over placebo on pain and other clinical core outcomes align with the results of several RCTs, systematic reviews and meta-analyses investigating the efficacy of cannabis-based medicines for different types of pain,” the researchers noted.
Patients in the CBD and placebo groups experienced a similar number of adverse events (median of four per patient). Common adverse events thought to be associated with the study medication included headaches/migraine, nausea/vomiting and having a dry mouth/throat. A greater number of serious adverse events occurred in the placebo group than the CBD group (eight versus two), but no serious adverse events were related to the trial treatment.
“These findings challenge the assumption that CBD is a beneficial analgesic for fibromyalgia and highlight the need for more rigorous evidence before recommending its use,” the researchers concluded.
“Clinicians may reconsider prescribing or endorsing CBD for fibromyalgia pain management based on this evidence.”
