Cannabis and the Risk of COVID-19
The racing locomotive of cannabis legalization and its seemingly limitless consumer consumption continues. Coupled with this growing demand, it’s appropriate to take an objective look at cannabis use as it relates to the SARS-CoV-2 (COVID-19) global pandemic and what risk smoking cannabis plays in COVID-19 pathology.
For decades it was assumed that smoking cannabis was harmless. As the veil of truth regarding the legitimate use of medicinal cannabis has slowly been unwrapped, so has the myth that smoking marijuana is as safe as previously thought. The method of ingestion of cannabis significantly affects its safety profile, since smoking cannabis (typically marijuana) generates free radicals, carcinogens, and a variety of toxic substances. Vaping cannabis from a cartridge (versus using dried flos) carries additional risks. *
Smoking cannabis, whether recreational or medical, has risks. It’s thought that the increased risk of smoking cannabis is the result of the reactive oxygen species (ROS), like free radicals, that are generated as a byproduct of combustion of the cannabis leaves rather than from the effects of inhaling cannabinoids. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5542986/) These ROS’s are by-products that cause damage to the cell and are seen are the precursors of diseases of chronic inflammation.
Persons smoking tobacco or cannabis increase their risk for pro-thrombotic (blood-clotting) diseases, like pulmonary embolisms and deep vein thrombosis. Chronic cannabis inhalation has been associated with a higher risk of an ischemic (like a rubber band tightly wrapped around your finger) stroke and heart attack. (https://pubmed.ncbi.nlm.nih.gov/19329702/) (https://pubmed.ncbi.nlm.nih.gov/28237318/) Marijuana smoking has also been associated with cardiovascular pathologies such as ventricular fibrillation, acute myocardial infarction (heart attack), and sudden death. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5542986/)
Although none of the above pathological factoids are new, under the backdrop of the unusual vascular pathology being seen in the COVID-19 pandemic, it’s worth looking at the data. Smoking cannabis increases a patient’s risk and susceptibility to a SARS-CoV-2 infection. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312781/)
Although primarily a respiratory infection, over a third of COVID-19 patients experienced some sort of neurological, or cerebral vascular symptoms, such as headache, dizziness, unstable walking, cerebral hemorrhage, or stroke. Additionally, a hallmark of COVID-19 is the sudden loss of smell or taste, an unusual and dramatic neurological symptom. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312781/)
The safety of using cannabis depends on how you’re using the plant, e.g., inhalation versus eating versus topical application. THC-rich recreational marijuana acts as a potent promoter of oxidative stress and inflammation. THC use is considered a risk factor for the onset of ischemic stroke, especially in the younger population. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4310259/) A recent report notes an increase in sudden strokes in patients between 30-40 (https://pubmed.ncbi.nlm.nih.gov/32343504/), a prime age demographic for marijuana use.
In addition to the respiratory complications from COVID-19, many patients suffer not only from pro-thrombotic events but also from blood-clotting disorders, (coagulopathies) where the risk of hemorrhagic stroke increases. A recent study showed a highly significant increase in stroke among cannabis users with estimates of an 11% increase in the risk of any stroke and a 41% increase in ischemic stroke. Cannabis was also associated with worse outcome from stroke.
A synopsis of case reports also suggest a link between using synthetic cannabinoids (e.g. Spice) and hemorrhagic stroke. Considering, the relative similarity in the strength of CB-1 stimulation between synthetic cannabinoids and THC concentrates like “dabbing” wax and shatter, the literature would strongly caution against the inhalation of all THC concentrates.
The safest methods of cannabis ingestion is topical application (such as a cream, salve, or ointment), oral ingestion (think brownies or gummies or using a tincture), and nasal sprays. Any topical or oral cannabis should be labeled with the dose of each product. The reason that the dosage of THC-infused products is so important is because the pharmacological onset of action of THC-infused products is significantly delayed, as compared to smoking. A person begins to feel high after taking a hit off a joint within seconds, whereas appreciating the effects of orally ingesting THC-infused products may take well over an hour. Considering the pharmacology of orally ingested THC, a naïve edible-user is at risk for a THC overdose, putting them at risk of cannabis vomiting syndrome and/or cannabis-induced psychosis.
If you want to minimize your risk of COVID-19 and cannabis-related morbidities, consider refraining from inhalational methods of cannabinoid delivery. The literature referenced above clearly suggests that smoking or vaping marijuana (or concentrated THC) puts the user at a greater risk for contracting COVID-19 (especially if the user is sharing a joint, pipe or a bong with others) as well as increasing the risk of COVID-19 vascular complications.
*The potential health risks of cannabis vaping are equally ominous as its e-cigarette cousin. Depending on the vaping product, THC and CBD, are not the only substances inhaled during vaping. In order to solubilize the cannabinoids, they must be dissolved in highly polar (fat-soluble) e-liquid, typically, propylene and diethylene glycol. How the various solvents and flavorings are chemically modified by the heat necessary to vaporize the e-liquid remains to be determined. Currently, there are no defined parameters and established guidelines concerning the preparation of the e-liquids and their composition. Flavoring agents (e.g., cinnamon, vanilla, and various fruits) in vape cartridges must also be considered as toxic inhalant agents. Flavoring agents are safe for use in food or confectionery products (ingested) are assumed to be equally safe when vaporized in the form of e-liquids (inhaled). Limited but steady evidence clearly suggests that these flavoring chemicals are present beyond the National Institute for Occupational Safety and Health (NIOSH) safety range and can be a potential irritant when directly inhaled.
Dr. Geci is the author of Pot Doc: A Physician’s Search for the Holy Grail of Medical Marijuana (2020)