Barcelona: According to research, cannabis used to treat chronic pain is associated with an increased risk of heart rhythm abnormalities. The study’s findings were published in the European Society of Cardiology. Study author Dr Nina Nauharvesh, from Gentoft University Hospital in Denmark, said: “Chronic pain is a growing problem. According to Danish health authorities, 29 percent of Danish adults over the age of 16 reported chronic pain in 2017, up from 2000. Medical cannabis was approved on a trial basis in Denmark in January 2018, meaning physicians can prescribe it for chronic pain if all other measures, including opioids, have proved insufficient. Data are sparse, so this study investigated the cardiovascular side effects of medical cannabis, and especially arrhythmias, as heart rhythm disorders have previously been found in recreational cannabis users.”
Medical cannabis comes in various formulations based on tetrahydrocannabinol (THC) and cannabidiol (CBD) levels. Dronabinol (high THC), cannabinoids (more THC than CBD), and cannabidiol (high CBD) may be prescribed in Denmark. The medicine can be inhaled, eaten, or sprayed in the mouth.
Researchers identified a total of 1.6 million patients suffering from chronic pain in Denmark between 2018 and 2021. Of those, 4,931 patients (0.31 percent) claimed at least one cannabis prescription (dronabinol 29 percent, cannabinoids 46 percent, cannabidiol 25 percent).
Each user was matched by age, gender and pain diagnosis with five non-users, who served as controls. Users and controls were followed for 180 days and their risks of new heart conditions were compared. The mean age of the participants was 60 years and 63 percent were female. The study reports, for the first time, the chronic pain status of medical cannabis users in Denmark. Some 17.8 percent had cancer, 17.1 percent had arthritis, 14.9 percent had back pain, 9.8 percent had neurological diseases, 4.4 percent headache, 3.0 percent complicated fractures, and 33.1 percent had other diagnoses (mostly unspecified chronic pain).
The absolute risk of new-onset arrhythmias in medical cannabis users was 0.86 percent, compared to 0.49 percent in non-users, for a relative risk of 1.74.
The risks of new-onset acute coronary syndrome and heart failure did not differ between the two groups. The results were similar for each chronic pain condition and each type of medical cannabis. Dr. Nowharvesh said: “Our study found that medical cannabis users had a 74 percent higher risk of heart rhythm disorders than non-users, however, the absolute risk difference was modest.
It should be noted that a higher proportion of those in the cannabis group were taking other pain medications, namely non-steroidal anti-inflammatory drugs (NSAIDs), opioids and anti-epileptics, and we cannot rule out that this could explain the greater likelihood of arrhythmias.”
She concluded: “Since medical cannabis is a relatively new drug for a large market of patients with chronic pain, it is important to investigate and report serious side effects. This study indicates that arrhythmias may occur before medical cannabis use. may have unreported risk. Even though the absolute risk difference is small, both patients and physicians should be more informed when weighing the pros and cons of any treatment.”