The Australian Rheumatology Association says it does not support the use of cannabinoids in routine clinical practice for the treatment of pain in arthritis and other musculoskeletal conditions.
In a new position statement the ARA says there is only weak evidence of efficacy in patients using cannabinoids, and the marginal benefits may be outweighed by harms and also the legal and practical problems associated with prescribing of medical cannabis.
The ARA says it recognises the growing interest in the use of medical cannabis for musculoskeletal conditions, particularly among people for whom there are currently few effective therapies for persistent pain.
However, while recognising the lived experience of some people who say they find it helpful for treating their symptoms, the ARA says there needs be evidence of efficacy and safety from rigorous randomised controlled trials before any potential intervention for arthritis and other musculoskeletal conditions can be recommended by practitioners.
“The current body of evidence for the use of cannabinoids for the treatment of arthritis and other musculoskeletal conditions is limited and provides low to moderate certainty evidence for marginal benefits which, for many, may be offset by harmful effects. As such, the adoption of cannabinoids into routine clinical practice in rheumatology is not supported by the ARA,” it says.
The advice to patients therefore is that “research so far shows that only a small number of people treated with cannabinoids for painful conditions notice a small improvement in pain and sleep, and there is little or no improvement in their ability to participate in daily activities.”
Patients should also be advised that they may experience unpleasant side-effects such as nausea and cognitive impairment, which in turn may make users unfit to drive or work with machinery.
The statement adds that patients who smoke cannabis or use cannabis products from non-medical sources will face further risks, and these should be avoided. Lack of long term safety studies means that there may be other long term adverse effects that we are not yet aware of.
However, it acknowledges that the use of cannabinoids for medicinal purposes is an area of rapidly-emerging research, and therefore the ARA will maintain its position statement as a ‘living document’ that is updated at least every six months, to recognise important new evidence or regulatory changes.
The statement summarises the evidence to date for the benefits of medical cannabis in arthritis as providing “moderate certainty evidence that use of non-inhaled cannabinoids probably results in a small increase (approximately 10%) in the proportion of people who experience at least a minimally important improvement in pain (1cm on a 10cm visual analogue scale).”
And while there is high certainty evidence that use of cannabinoids results in a very small increase in the proportion of people who achieve a minimally important improvement in sleep quality (approximately 6%) or physical functioning (approximately 4%), there is no improvement in emotional, role or social functioning.
Only a small number of the trials of medical cannabis for chronic non-cancer pain have involved people with rheumatological conditions such as rheumatoid arthritis, osteoarthritis, fibromyalgia, and none of the trials related to use for longer than six months.