Research links weed to higher risk of stroke, but experts say clearer data is needed before jumping to conclusions

According to experts, dose, frequency, treatment intention and mode of administration matter.


                            Research links weed to higher risk of stroke, but experts say clearer data is needed before jumping to conclusions

Using marijuana frequently among young people has been linked to a higher risk of stroke in a recent study. Another study has associated cannabis use disorder to serious heart rhythm abnormalities.

Experts, however, caution that clearer and scientifically rigorous data is needed before one can jump to life-threatening consequences of using marijuana or cannabis. 

Dr Sherry Yafai, medical director at Releaf Institute, US, and adjunct assistant professor at John Wayne Cancer Institute, US, told MEA WorldWide (MEAWW) that cannabis is a broad umbrella and more specific discussions need to be had, and like all medications and drugs, dosage, frequency treatment intention and mode of administration matter. 

Explaining her point, Dr Yafai says medications such as tylenol or acetaminophen (both prescribed to reduce pain and fever) are generally regarded as safe. But when taken excessively or in larger than recommended doses can be damaging or life-threatening to the liver. 

“To date, there has not been one death directly attributed to the plant. There are now multiple deaths associated with lung disease from additives to vape pens, again not directly linked to the plant. So to make the jump to life-threatening is extreme. That being said, patients with a history of heart disease and pulmonary disease should consult a physician before taking cannabis products as medications and underlying cardiovascular health should be taken into consideration when taking a cannabis-based medication,” Dr Yafai, co-vice president of the Society of Cannabis Clinicians, told MEAWW.

She cautions that recreational and medical cannabis use should not be lumped together. “Too often I see recreational cannabis use and medical cannabis use lumped together. This would be akin to saying heroin and medical/hospital morphine are the same. Why is it that when we discuss other pharma/recreational drugs, we have drawn lines in the sand and not when discussing cannabis?” she questioned.

Dr Robert Harrington, president of the American Heart Association and chairman of the department of medicine at Stanford University, California, also emphasizes that as these products become increasingly used across the country, getting scientifically rigorous data is going to be important “as we try to understand the overall health effects of cannabis.” 

Dr Sherry Yafai, medical director at the Releaf Institute and adjunct assistant professor at John Wayne Cancer Institute, says recreational cannabis use and medical cannabis use must not be lumped together. This would be akin to saying heroin and medical/hospital morphine are the same, she says. (Getty Images)

Dr Yafai says that to date, she is aware of two pediatric cases of accidental ingestion of large amounts of tetrahydrocannabinol (THC) edibles that caused a “cardiac pause that self-resolved,” which implies no intervention from the doctor was required. Both cases were monitored closely and resolved without long term damage. 

She says when patients choose to self-medicate, and when medications are left in the hands of the individual, there are risks. To date, these risks have been small, but as the cannabis industry becomes driven by money and potentially lucrative business, these risks become greater, says Dr Yafai. Accordingly, she cautions that people must be mindful when they use cannabis, THC, and cannabidiol (CBD) recreationally, which includes the dose and the packaging.

“Yes, cannabis, THC, and CBD have effects on the cardiovascular system due to cannabinoid receptors (CBD1 and CBD2 Receptors) located on the cardiovascular system. Yes, we need more data, and we need to be more mindful of recreational usage, including dosage and packaging. We need to be aware that 1 mg of THC and 10 mg of THC will not affect individuals the same. The next step is to talk about cannabis as more than recreational. We need to talk dose, we need to talk chemicals, we need to educate clinicians and the public,” she told MEAWW.

Dr Yafai explains that cannabis is not the same as it was in the 1970s when all anyone could access was THC-dominant flower, which is approximately 3-7% concentration. However, currently, access to THC, CBD, hemp, cannabis is available in a staggering amount of concentration and dosage variation is available in smokable (flower, oil, dab, shatter) edible (sublingual, oil, honey, tea, brownies, cookies, chocolates, etc.) and topical varieties.

“We need to emphasize the very specifics of what we are talking about. We do have studies showing the safety parameters of CBD and THC to a certain extent. But much like all medications, drugs, toxins, etc., dosage, frequency, mode of administration matters. THC smoked from the flower has a large safety profile, when referred to as single usage. When this is adultered into dab/shatter/vape oil, the safety profile changes. When other additives (that is, vitamin E acetate is added), we are seeing toxicity to the lungs,” she told MEAWW.

The US Centers for Disease Control and Prevention (CDC) has linked certain e-cigarettes or vaping products containing a cannabis compound, THC, to the lung injury outbreaks in the US. The CDC also recently identified vitamin E acetate as a cause of lung injury outbreaks in the US. 

The two studies were recently presented at the American Heart Association’s Scientific Sessions 2019.

According to one study, young people who used cannabis frequently and also smoked cigarettes or used e-cigarettes were three times more likely to have a stroke compared to non-users. The findings, which will be published in Stroke, however, show only a “potential link”.

The researchers also said that cannabis users, who did not use tobacco products but reported using cannabis for over 10 days a month, were nearly 2.5 times more likely to have a stroke compared to non-users. There were over 43,000 adults in the study, aged 18 to 44, of whom nearly 14% reported using cannabis in the last 30 days. Compared with non-users, marijuana users were often younger, non-Hispanic white or black were less likely to be college graduates and were often physically active.

In the second separate study, the researchers said people diagnosed with cannabis use disorder had a 50% greater risk of being hospitalized for an arrhythmia, a disorder of the heart’s rhythm, compared to non-users. Cannabis use disorder is characterized by frequent, compulsive use of marijuana, similar to alcoholism.

“As medical and recreational cannabis is legalized in many states, it is important to know the difference between therapeutic cannabis dosing for medical purposes and the consequences of cannabis abuse,” says Dr Rikinkumar S Patel, resident physician in the department of psychiatry at the Griffin Memorial Hospital in Norman, Oklahoma, author of the second study.

Experts say when patients choose to self-medicate, and when medications are left in the hands of the individual, there are risks. To date, these risks have been small, but as the cannabis industry becomes driven by money and potentially lucrative business, these risks become greater. (Getty Images)

The researchers of the second study said that young African American men with the disorder, between 15 to 24 years of age, had the greatest risk of being hospitalized for arrhythmia, although cannabis use disorder was more common among white men, aged 45 to 54.

According to Dr Yafai, the way this is written is ‘misleading.’ She explains cannabis use disorder is poorly diagnosed by clinicians who have little to no education on cannabis. It is also likely underdiagnosed as many who are addicted to cannabis products due not reach out to healthcare providers, she says. 

“The fact that young African American males are being attributed to having an increased likelihood for arrhythmias, even though they are not the group with the most use, is contradictory to these findings. Wouldn’t you expect the group with the largest use to have the most risk? If the group with the lower usage has greater problems, isn’t it more likely due to other factors, that is, known genetic hypertension and hypercholesterolemia known to affect African American males?” questioned Dr Yafai.

According to her, the two studies cannot be regarded as either alarming or surprising as everything we put in our bodies has a benefit and risk. 

“A slice of chocolate cake can be delicious and evoke happiness when eaten. A whole chocolate cake can lead to diabetes. A single cannabis flower can help with pain, insomnia, and cancer/chemo treatments. Ingesting 100 mg of THC can cause arrhythmias, low blood pressure, nausea, vomiting, and a panic attack. Dose and treatment intention matter. We have limits on the amount of acetaminophen that is sold, isn’t it time we recognize that we need limits on this as well?” Dr Yafai told MEAWW.

She said limits on legal, non-pesticide, organic cannabis products might be what is best for the nation. She says the education of clinicians should also go hand-in-hand to help individuals who are on multiple medications. 

“Similar to all other mediations, I urge each state to create standards for medical education in conjunction with other policy decisions,” says Dr Yafai.

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