New research out of Denmark suggests that medical marijuana use for chronic pain issues may significantly increase a person’s risk for de novo arrhythmia compared to patients who pursue other treatments for their pain.

While the absolute risk of developing heart arrhythmia while taking medical cannabis for a chronic pain condition is still relatively low (0.4%), the fact that is raises your risk at all could be a cause for concern for many patients, especially those with a history of heart issues.

“Short-term risk of arrhythmia was significantly elevated in patients prescribed medical cannabis compared with matched control patients, but the absolute risk increase was modest at 0.4% in the first 180 days,” said Anders Holt, MD, cardiologist at Copenhagen University Hospital – Herlev and Gentofte in Denmark, in an interview with Healio.

Medical Cannabis And Heart Issues

For their research, Holt and colleagues used nationwide registers to identify 5,391 patients with chronic pain who began using medical cannabis between 2018 and 2021 as part of their treatment plan. This group was then age- and sex-matched 1:5 to 26,941 control patients with a chronic pain diagnosis that were pursuing another pain medication treatment other than medical cannabis.

For the patients that used medical cannabis:

• 24% used CBD
• 29% used combination CBD/THC
• 47% used THC alone

For patients pursuing other treatments, the most common medications were NSAIDs, anti-epileptic drugs and opioids.

Researchers reported that medical cannabis use was associated with a 180-day absolute risk for new-onset arrhythmia of 0.8%, whereas non-use was linked to a 180-day absolute risk for new-onset arrhythmia of 0.4%, meaning patients who pursued medical cannabis were twice as likely as their counterparts to develop a new heart arrhythmia. Researchers said the increased arrhythmia risk was similar regardless of the type of medical cannabis they pursued.

“Both CBD and THC have an effect on the CB1R receptor, which theoretically could lead to CV [cardiovascular] side effects,” said Holt. “Previously, side effects have been mostly suspected to be related to THC since the psychoactive properties of cannabis arise from this cannabinoid. Findings from this study suggest that both THC and CBD may play a role in the risk of CV side effects.”

The team did note that they observed no significant association between medical cannabis use for chronic pain and risk for acute coronary syndrome

“This study adds important and much-needed data on CV side effects related to medical cannabis; however, clinicians should consider the observational nature of these findings which limits their impact and applicability for clinical recommendations before changing any practice,” Holt concluded. “Considering all available data on medical cannabis treatment for chronic pain, I believe that it should probably be reserved for chronic pain conditions where the effect is supported by sufficient evidence, eg, neuropathic chronic pain. Considering data from this study, some improved monitoring of CV symptoms immediately following initiation could be beneficial, especially in patients with known cardiometabolic disease or history of cancer.”

Dr. Holt’s takeaway point here is key. Given the nature of the study results, physicians should thoroughly review a patient’s heart history before recommending medical cannabis as a treatment option, and heart monitoring could be beneficial for chronic pain patients who are beginning a medical cannabis regimen. Medical cannabis has been shown to be an effective tool in managing symptoms for many types of chronic pain patients, but it’s not without its own risks. Patients would benefit from an open and honest dialogue with their doctor about their heart health prior to beginning a medical cannabis regimen as part of treatment for their chronic pain condition.

For more information about medical cannabis or chronic pain treatment, reach out to Dr. Cohn and his team today at (952) 738-4580.