High blood pressure affects up to one in five people in New Zealand.
It’s known as the “silent killer” because it often shows no symptoms and puts people at increased risk of heart disease, heart attacks, stroke, and other serious conditions.
Coronary artery disease and stroke are the number one causes of death and disability in New Zealand, taking a life every 90 minutes on average.
While conventional treatments or hypertension can be effective, some have unpleasant side effects or can’t be used if other pre-existing medical conditions are present.
A new study has found that medicinal cannabis may help to reduce blood pressure in older patients.
The findings of this study, while limited, should be of interest to people who have high blood pressure and a family history of heart disease, as well as doctors and healthcare professionals who are seeing the effects of hypertension every day.
The cannabis-blood pressure connection
The study by Israeli researchers, published in 2021, looked at 26 patients over the age of 60 before and three months after starting to use prescription medical cannabis.
The aim of this study was to assess the effect of cannabis on blood pressure, heart rate, and other metabolic measures in older adults with hypertension.
“Older adults are the fastest growing group of medical cannabis users, yet evidence on cardiovascular safety for this population is scarce,” the study says.
“This study is part of our ongoing effort to provide clinical research on the actual physiological effects of cannabis over time.”
Patients had their blood pressure monitored over 24 hours, an electrocardiogram (ECG), blood tests, and body measurements taken prior to starting cannabis therapy and three months afterward.
The study found that participants’ blood pressure — both systolic and diastolic — reduced by 5.0mmHg and 4.5mmHg, respectively, after three months of using medicinal cannabis.
The authors say the reductions in blood pressure were “statistically and clinically significant”.
However, they were not enough to consider medicinal cannabis as a treatment for hypertension on its own.
It also found that the proportion of “dippers” — people whose blood pressure falls at night — increased from 27.3% before using medicinal cannabis to 45.5% after treatment.
THC or CBD for hypertension?
Most of the participants in this study used cannabis oil with varying amounts of THC and CBD.
A small number (15.4%) of participants smoked cannabis.
About a third of the participants used cannabis once a day, a third used it twice a day, and a third used it more than three times a day.
The study found no dose-response relationship between either THC or CBD and blood pressure, meaning it didn’t appear that one cannabinoid was more effective than the other.
A study published in 2017 found that resting blood pressure was lower after subjects had taken CBD and that CBD blunted the blood pressure response to stress.
There have been a handful of other studies that found that cannabis use increased systolic blood pressure.
Pain reduction and blood pressure
The researchers proposed that the pain-relieving properties of cannabis may have contributed to the reduction in blood pressure.
Chronic pain is associated with hypertension and older people are more likely to experience chronic pain.
If the cannabis provided participants with pain relief, it may have indirectly affected blood pressure.
However, this is just a theory and didn’t form part of the study.
The first of its kind
The study was the first to look at the relationship between medicinal cannabis and blood pressure in this way.
And while the results are promising on the surface, there were several limitations to the study.
There was no control group, the levels of THC and CBD were not consistent, and the immediate effects of using cannabis were not measured.
It would not be a good idea to switch your blood pressure medication for cannabis based on the results of this study alone.
Given the prevalence of high blood pressure in New Zealand and around the world, and the often devastating effects of this “silent killer”, the findings of this study are significant.
However, more research is needed before medicinal cannabis can be considered a safe and effective treatment for high blood pressure.