Clients of Arthritis New Zealand often ask for advice on using cannabis to help them manage their arthritis. So, what are the benefits and risks of the medicinal use of cannabis?

Our aim in this article is to present information about potential benefits and known risks and to encourage informed discussion about the use of cannabis products. Arthritis New Zealand does not recommend using cannabis or any specific cannabis products. These are decisions for individuals in consultation with their doctors.   

Important things to know before you consider using cannabis

While people using cannabis often believe it helps them manage their condition, some may not fully understand the downside risks. It is essential to study these and seek medical advice.  Cannabis is a complex plant made up of over 400 different chemicals, including about 100 cannabis-specific chemicals called cannabinoids.  Tetrahydrocannabinol (THC) produces the “high” experience, and cannabidiol (CBD) does not.

Cannabis products that get patients high or are smoked pose some risks:

•    Any form of smoking is bad for your lungs. Smoked cannabis also produces other negative impacts on your body. 

•    Young rheumatology patients risk harm to their brain’s development.

•    Cannabis use can lead to dependency and reduced productivity.

•    The “high” from cannabis impairs judgement of distance and time so is dangerous for drivers and some workers. Older people can experience increased difficulty with balance.

•    Cannabis can make people with mental health issues that involve psychosis more unwell.

•    Potential for unwanted exposure to herbicides and pesticides.

Risks of CBD products

The US National Institute on Drug Abuse (NIDA) concluded in 2015 that “CBD appears to be a safe drug with no addictive effects and the preliminary data suggest that it may have therapeutic value for a number of medical conditions.”      MedlinePlus indicates that CBD products can sometimes interact with certain prescription medications, primarily those that are “changed and broken down by the liver”. This concern regarding medicines interactions give credence to the legal requirement that CBD products are only available via prescription.

How can cannabis help people with arthritis?

A 2017 review of available evidence by the US National Academy of Sciences concluded

•    there is substantial evidence that cannabis is an effective treatment for chronic pain in some adults. The 2017 review says, “conclusions across all of the reviews were largely consistent in suggesting that cannabinoids demonstrate a modest effect on pain.” While not the magic bullet for pain, use of cannabis products have shown to be associated with reduced use of opioids.

•    there is moderate evidence that cannabinoids, primarily nabiximols (trade name Sativex), are an effective treatment to improve short term sleep outcomes in individuals with sleep disturbance associated with fibromyalgia and chronic pain.

A recently released literature review from the Medical Research Institute of New Zealand notes, however, that little research has focused specifically on arthritic pain. The reviewers found one study that showed positive impacts on pain for people with rheumatoid arthritis through use of Sativex. They noted that overall, the evidence to support pain relief from cannabis for arthritis is weak compared to the evidence to support the use of current treatments for pain. The researchers were unable to find any human studies that assessed CBD only preparations in osteoarthritis or rheumatoid arthritis.

Some studies suggest benefits other than pain management. For example, a 2019 presentation to the American College of Rheumatology, concluded that preclinical research has found some cannabis products to have a positive impact on inflammation. Still, it also says that clinical research has been weak.

Clinical research determines the safety and effectiveness of medicines for human research and is conducted on humans. Preclinical research is often done on animals. Clinical cannabis research is difficult to summarise as experiments have usually been conducted in a way that makes review difficult as research methods are too different to provide reliable comparison across many studies.

In summary, there is evidence that cannabis can help with chronic pain, but little reliable research has explicitly focussed on arthritic pain. Arthritis-focused research is now underway, but results will not be available for some time. There are risks of using cannabis, especially of smoking it. Consulting your doctor is an excellent first move.   

More information and references

  1. National Institute on Drug Abuse
  2. Medicinal Cannabis – The Canadian Perspective
  3. Cannabis-based medicinal products in arthritis, a painful conundrum, Van de Berg M, John M, Black M, Semprini A, Oldfield K, Glass M, Braithwaite I. New Zealand Medical Journal 22 May 2020.

See the following websites for information about cannabis and health

NHS – Cannabis: the Facts

WHO – The health and social effects of nonmedical cannabis use

WebMD – How Pot Affects Your Mind and Body

PHARMAC – Medicinal Cannabinoids

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