A small placebo-controlled trial shows that daily doses of cannabis oil rich in THC (tetrahydrocannabinol) significantly improves pain, fatigue and quality of life in people with fibromyalgia.
The study findings, recently published in the journal Pain Medicine, involved 17 women with fibromyalgia living in Florianopolis, Brazil. Participants were given drops of cannabis oil or a placebo for eight weeks, starting with an initial dose of one drop a day orally and then titrating to an average of 3-4 drops a day.
The cannabis oil used in the study contained 1.22 mg of THC and 0.02 mg of CBD (cannabidiol) per drop. THC is the psychoactive ingredient in marijuana.
The women self-reported their symptoms on a questionnaire every 10 days. Few changes were noted in the placebo group, but the women receiving cannabis oil reported significant improvement on a wide range of symptoms, including pain, depression, anxiety and fatigue. They were also more likely to “feel good” and not miss work compared to the placebo group.
“To our knowledge, this is the first randomized controlled trial to demonstrate the benefit of cannabis oil – a THC-rich whole plant extract – on symptoms and on quality of life of people with fibromyalgia,” researchers said. “During the intervention, the impact of the intervention on quality of life in the cannabis group participants was evident, resulting in reports of well-being and more energy for activities of daily living. Pain attacks were also reduced, albeit subjectively, in frequency and intensity.”
The researchers concluded that cannabinoids can be a low-cost and well-tolerated therapy for fibromyalgia patients, and recommended that it be included as an herbal medicine option in Brazil’s public health system.
“The demonstration of safety and efficacy in this gold-standard model is significant. Millions of Americans suffer with FM (fibromyalgia) – a condition that tends to be poorly controlled by standard medicines. These clinical findings indicate that for many of these patients, plant-derived cannabis preparations may be a safe and effective alternative,” said Paul Armentano, Deputy Director of NORML, a pro-marijuana advocacy group.
A major weakness of the Brazilian study is its small size. Participants also continued to self-medicate with analgesics and anti-inflammatory medications during the study, which could have affected the findings.
A larger 2019 study in Israel also found that cannabis reduces pain and improves quality of life for fibromyalgia patients. The cannabis used in that study was ingested by tincture, oil or vaporizer.