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What We Don't Know About CBD Products Could Hurt You

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Frieda Wiley, PharmD - Blogs
By Frieda Wiley, PharmD, RPhSeptember 27, 2019
From the WebMD Archives

Medical marijuana has always been a popular - and not to mention, controversial - topic. But now, its grandchild, cannabidiol (CBD), is enjoying its own 15 minutes of fame. These days, it's virtually impossible to turn on the TV, surf the ‘net, or even cruise down the street without seeing or hearing something about CBD. 

Though CBD comes from the same plant as marijuana, CBD has little, if any, tetrahydrocannabinol (THC), the chemical that gives marijuana its euphoric or hallucinogenic effects. So, as long as the amount of THC falls below a certain amount, CBD products are legal to sell (though that doesn’t guarantee that the products are entirely safe).

CBD is used to treat many health conditions such as seizures and other neurological disorders, pain, and inflammation. CBD comes in a wide variety of products and dosages: You can find CBD sold in tinctures, gummies, capsules, lozenges, oils, vape pens, sprays, creams, and suppositories, and more. But not all CBD products are safe - or are created equal. And the jury’s still out on the quality of these products and how well they work.

To get a better handle on the challenges, I spent some time chatting with my colleague, Michael Schuh, PharmD, MBA, FAPhA, a clinical pharmacist and assistant professor of family medicine, palliative medicine, and pharmacy at the Mayo Clinic in Florida. He also happens to be an expert in integrative medicine and CBD. 

What’s the biggest misconception about CBD?

CBD is like a potent herbal supplement, but what many people don’t realize is that CBD has side effects and drug interactions just like any drug. Basically, if it’s a strong enough dose to cause therapeutic effects, it’s enough to cause side effects and drug interactions. Another problem is that few of the products are standardized or vetted to make sure you’re getting a pure and high-quality product. This makes it hard to know what you’re really using. In fact, there’s no real way to vet CBD products right now. Anything that you swallow, inhale, inject, or absorb through your skin that has direct contact with your bloodstream has a risk of unforeseen side effects or interactions. 

Many companies say that CBD products are completely safe, but you mentioned that CBD products have drug interactions that are not widely known. Can you give us an example?

The liver plays an important role in how drugs work because it contains special catalysts, or enzymes that activate drugs so they can take an effect on the body. These enzymes may also help remove these drugs from the body after they’ve done their job. CBD slows down the liver enzymes' ability to activate drugs so they work and their ability to break down drugs that are removed from the body. One example is clopidogrel, an antiplatelet drug used to prevent stroke or heart attack. If you’ve already had a heart attack and are trying to prevent another one, taking CBD may keep the liver from converting clopidogrel to its active form, resulting in another heart attack. There’s evidence that CBD also inhibits other enzymes that break down at least 50-60% of all prescription drugs. These enzymes break down opioids and other drugs that depress the nervous system, or CNS depressants. If you inhibit any one of these pathways, you may risk a drug overdose because your body can’t clear CNS depressants as quickly as it should. That’s because CBD slows down how quickly your body processes CNS depressants, so your body doesn't process them as quickly as it normally would. As a result, CNS depressants can rise to rise to dangerously high levels. 

Given the issues with ensuring quality of CBD products you’ve highlighted, what are the key pointers you can offer readers to help them make better informed choices about CBD products?

CBD alone is a depressant. It has no euphoria, but is still a nervous system depressant even without THC.

Patients should contact their doctor or pharmacist about CBD. Unfortunately, even most of these health care professionals don’t know the real literature evidence about CBD. I recommend patients only rely on information they find on websites operated by the U.S. federal government, research universities and academic sites, such as the Mayo Clinic.

Understand that money is driving the CBD industry—not clinical efficacy. Only in rare pediatric seizure disorders does it have some current acknowledged clinical value.

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About the Author
Frieda Wiley, PharmD, RPh

Frieda Wiley, PharmD, RPh, is a clinical pharmacist, contract medical writer, and consultant. She has numerous publications to her credit, including O! The Oprah Magazine,Arthritis Today, US News & World Report, Everyday Health, and Costco Connection. To read more about Frieda, visit her website or follow her on Twitter.

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