Patients taking medical cannabis for chronic pain have a higher risk of developing arrhythmia, according to a study published in the European Heart Journal. Patients with arrhythmia have an irregular heartbeat, which may be too fast or too slow. It also includes conditions like atrial fibrillation.
Doctors know that recreational use of cannabis is linked with an increased risk of cardiovascular disease, but there’s very little research about the use of medical cannabis. The team advocates that this is important as a growing number of countries now allow the use of cannabis to treat chronic pain.
This study included data from over 5000 participants who were prescribed cannabis for chronic pain. This included patients with severe muscle or nerve pain as well as cancer. These results were compared with over 25,000 patients with chronic pain but not treated with cannabis.
The data suggests that medical cannabis more than doubled the risk of being diagnosed with arrhythmia within 180 days of taking cannabis, but this risk dropped after the first year of treatment. Patients over 60 and those already diagnosed with cardiovascular conditions, such as heart disease, stroke, and diabetes, had the most significant increases in their risk of arrhythmia.
“Medical cannabis is now allowed as a treatment for chronic pain in 38 US states as well as several countries in Europe – such as Spain, Portugal, the Netherlands and the UK – and elsewhere around the world. This means more and more doctors will find themselves prescribing cannabis, despite a lack of evidence on its side effects,” said Dr. Anders Holt from Copenhagen University Hospital – Herlev and Gentofte in Denmark. “I don’t think this research should make patients with chronic pain refrain from trying medical cannabis if other treatment has been inadequate. However, these results do suggest some improved monitoring may be advisable initially, especially in patients who are already at increased risk of cardiovascular disease.”
The authors highlight that more research is needed, including replicating this study in other countries and settings. It seems that medical cannabis may not be the “one size fits all” option for patients with chronic pain, but the decision to use it should depend on the patient’s comorbidities and vulnerability to side effects. It would also be interesting to find out if there are any links between long-term use of cannabis and heart failure, stroke, or acute coronary syndrome.
Anders Holt, Nina Nouhravesh, Jarl E Strange, Sebastian Kinnberg Nielsen, Anne-Marie Schjerning, Peter Vibe Rasmussen, Christian Torp-Pedersen, Gunnar H Gislason, Morten Schou, Patricia McGettigan, Morten Lamberts, Cannabis for chronic pain: cardiovascular safety in a nationwide Danish study, European Heart Journal, 2024;, ehad834, https://doi.org/10.1093/eurheartj/ehad834