When the COVID-19 pandemic began, no drugs were specifically made to treat it. Researchers began investigating how to repurpose other drugs to fight COVID-19, including cannabis. Drug repurposing is when scientists find new uses for medicines that were already made for different reasons.
While early studies with cannabis show potential for preventing an infection that could lead to COVID-19, researchers are still learning how safe and effective this treatment could be. Continue reading to learn more about how cannabis and cannabis products might be used to treat and prevent COVID-19.
Cannabis — also known as marijuana or weed — comes from a plant with the scientific name Cannabis sativa. It produces several compounds that can affect different parts of the body, including the brain and immune system. The active compounds from cannabis are called cannabinoids.
There are two main types of cannabinoids — tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the component that makes you feel “high” or euphoric by producing a drug-like effect in people. CBD can affect the body without causing the “high.” Cannabinoids are being studied to see if they benefit people with different health conditions, including:
Cannabis can be taken by mouth or by inhalation. You can consume it as baked goods or edibles, drink it in tea, or apply it using a spray under the tongue. Smoke or vapor from burning the dried leaves or resin can also be inhaled into the lungs.
In the United States, cannabis is classified as a Schedule 1 controlled substance. This means the federal government considers cannabis a drug with a high potential for abuse without an accepted medical use.
However, several states in the U.S. have legalized cannabis for medical or recreational use. Additionally, there are several prescription drugs approved by the U.S. Food and Drug Administration (FDA) that contain cannabinoids, including:
Another drug, nabiximols (Sativex), is approved in Canada to treat pain related to cancer and multiple sclerosis.
Researchers observed that people taking CBD-based medications were less likely to report catching COVID-19 than other people. While there aren’t any clinical trials specifically testing whether CBD can prevent COVID-19 in humans, researchers have tested it in mice. When researchers gave mice CBD before exposing them to the virus, they were less likely to develop COVID-19 than mice that didn’t get CBD.
In laboratory tests cited in the journal Clinical Science, scientists found that cannabinoids may prevent cells from getting infected with the virus that causes COVID-19 — called SARS-CoV-2.
In a 2022 study from the journal Science Advances, researchers introduced the virus to human lung cells treated with cannabinoids in a laboratory. They found that the virus had a more difficult time infecting lung cells with CBD. However, when CBD was combined with THC, the protection was decreased. Another laboratory study published in the Journal of Natural Products also found that CBD can block SARS-CoV-2 from entering human cells.
Although these results seem promising, clinical trials in humans are needed to see if the results from the laboratory will lead to a benefit in the real world.
Researchers are also studying cannabis to see how it can affect the symptoms and severity of COVID-19. So far, studies have had mixed results.
One study looked at the difference in outcomes for people admitted to the hospital with COVID-19. They found that people with COVID-19 who reported using cannabis were less likely to need intensive care or mechanical ventilation than those who didn’t use cannabis. However, the cannabis users were also younger and less likely to have diabetes, so those things alone may have made it less likely for them to need intensive care than the other people studied.
Another study from the journal Molecular Psychiatry found that people with substance use disorder, including cannabis use, had an increased risk of hospitalization and death with COVID-19. However, a different study published in Frontiers in Genetics using the same data suggested that cannabis use may actually decrease the risk of getting COVID-19 — although the researchers stated that their findings “do not encourage cannabis use.”
More research is needed to find out if cannabis helps with COVID-19 symptoms. However, scientists think if there is a potential benefit, it may be because cannabis can have anti-inflammatory effects on your immune system.
A study showed that CBD might lower levels of inflammation-causing proteins called cytokines. This finding was seen in lab tests using human lung cells and mice. Decreasing cytokine levels could help to prevent a life-threatening complication of COVID-19 called cytokine release syndrome, also known as cytokine storm. People with cytokine storm can have more severe COVID-19 symptoms and organ damage.
If you smoke cannabis, you may have many of the same risks as people who smoke cigarettes. Cannabis smoke contains harmful chemicals that are similar to what’s found in tobacco smoke. Although it’s not proven with clinical trials, smoking cannabis may increase your risk of severe COVID-19 symptoms in the same way as people who smoke cigarettes.
Cannabis may also put you at risk for other serious mental health conditions. One study from the Journal of Cannabis Research found that cannabis use was associated with an increased risk of developing delirium (confusion and lack of awareness) in people hospitalized for COVID-19.
Other possible side effects of cannabis and other cannabinoids include:
Cannabis may cause addiction in some people. If you suddenly stop using cannabis regularly, it may cause withdrawal symptoms, such as:
Although researchers investigate using cannabis as a complementary and alternative medicine (CAM) for COVID-19, many doctors don’t recommend it.
Most cases of COVID-19 can be treated at home. You can manage your COVID-19 symptoms by using over-the-counter (OTC) medications like ibuprofen (Motrin or Advil) or acetaminophen (Tylenol).
The CDC notes that if you have a higher risk of getting very sick from COVID-19, a health care provider can prescribe a treatment that can reduce your risk of going to the hospital or dying from COVID-19. These medications are antiviral treatments that block the virus from multiplying in your body. The available antiviral medications include:
Cannabis isn’t a reliable way of preventing COVID-19. The dose of cannabinoids needed to prevent a SARS-CoV-2 infection is most likely much higher than the dose you can get by using recreational or medicinal cannabis products. Additionally, there is a risk of side effects and addiction to cannabis products.
To protect yourself and others from getting COVID-19, the Centers for Disease Control and Prevention (CDC) recommends the following:
The CDC has reported cases when people have been seriously harmed using alternative medicines to treat or prevent COVID-19. Talk to a health care provider before taking any medication for COVID-19, even OTC medications and supplements.
On myCOVIDteam, the online support network for people and their loved ones recovering from the effects of COVID-19, you can connect with others. More than 8,000 members come together to ask questions, give advice, and share their stories with others who understand life with COVID-19.
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