If you're an aging baby boomer who thinks you can handle today's potent marijuana "edibles", the case of a man who had a heart attack after eating a dagga lollipop should give you pause.
The 70-year-old patient had been taking heart medications and consumed roughly 90mg of THC while trying to ease pain and aid sleep. That's a far greater amount than the 7mg of THC that is typically found in a single joint. THC is the ingredient in marijuana that makes you high.
A heart attack ensued after the man felt crushing chest pain and experienced a sudden reduction of blood flow to his heart, his Canadian doctors reported.
The patient survived, noted study author Dr Alexandra Saunders. But, "we thought this case report was important to publish because it was about a person with known heart disease and risk factors for heart disease, which is an ever-growing part of our population," Saunders said.
Although the man had smoked dagga when he was young, average THC counts have since risen considerably. Nor had the patient understood that the effects of edibles kick in more slowly, are more powerful and last longer, noted Saunders, who is chief resident of the department of cardiology's internal medicine programme at Dalhousie University in Saint John, New Brunswick.
"What we presume about this event is that the intense stress caused from his fearful hallucinations caused him to have undue stress on his heart, making his heart beat faster and blood pressure go up in such a way that his coronary arteries were not able to meet the demand for blood supply," Saunders explained.
THC-prompted blood vessel inflammation may also have played a role, though Saunders said this possibility requires more research.
That said, the researchers noted that the typical THC dosage in synthetic medicinal marijuana products specifically intended for nausea control and appetite stimulation (often as a treatment for AIDS and/or cancer) is just 2.5 mg.
So, would those products have been safe?
"That is the part that we do not know at present and have no guidance on," said Saunders, adding that while the researchers "assume that a smaller dose certainly would have put less of a stress on the heart, [there are] no studies or data to support this."
Regardless, Saunders said that "this case brings attention to the fact that just because something is legal, does not mean it is safe and does not mean it is something that should be taken by everyone. We do not want to demonise it, we just want our older patients with heart disease to have proper guidance."
Saunders encouraged consumers to familiarise themselves with the THC content of any marijuana product, and to take the form of the product into account. For example, pot lollipops are not intended to be consumed all at once, despite what many might presume.
Consult your doctor
Paul Armentano, deputy director of the marijuana legalisation advocacy organisation called NORML, said that his organisation has "long recognised that THC exposure can influence blood pressure and heart rate, particularly in more naive consumers".
As a result, he said, "there may be some populations that may be vulnerable to increased risks from the use of cannabis", including adolescents, pregnant women, nursing mothers, heart disease patients and those with a personal or family history of psychiatric illness.
"As with any medication, patients should consult thoroughly with their physician before deciding whether the medical use of cannabis is safe and appropriate," Armentano added.
To date, Canada has only legalised marijuana leaves for recreational use, although marijuana edibles are scheduled for legalisation later this year.
In the United States, marijuana is banned on a federal level, although it is recreationally legal in Washington, DC and 10 states: Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, and Washington.
Medical marijuana use is legalised in 33 states, and Washington, DC.
The case report was published online Feb. 11 in the Canadian Journal of Cardiology.
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