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Cannabidiol (CBD), has gained widespread attention for its potential to ease symptoms of insomnia, anxiety, chronic pain, and a host of other health conditions.

And while studies are ongoing as to how effective CBD is, many people are giving it a try.

Research to date shows that CBD is generally safe and has few, if any, minor side effects. But there’s one big caveat: CBD does have the potential to interact with some medications. The concern has to do with how the body metabolizes certain substances.

Before trying CBD, it’s crucial to talk to your doctor about all of the vitamins, supplements, and prescription and over-the-counter medications you’re taking. Here’s a deeper look at why having the conversation matters.

When you take a medication or other substance, your body has to metabolize it, or break it down. Drug metabolism happens throughout the body, such as in the gut, but the liver does a big part of the job, too.

A family of enzymes called cytochrome P450 (CYP450) does the important work of converting foreign substances so they can easily be eliminated from the body.

But some medications or substances affect CYP450, either by slowing or speeding up drug metabolism. That change in metabolism rate can alter how your body processes the medications or supplements you take — hence a drug interaction.

Why does CYP450 matter when it comes to CBD and medications?

The CYP450 family of enzymes is responsible for metabolizing several cannabinoids, including CBD, research shows. Specifically, CYP3A4, an important enzyme within the CYP450 family, does the task. But during this process, CBD also interferes with CYP3A4.

The CYP3A4 enzyme is in charge of metabolizing about 60 percent of clinically prescribed medications. But if CBD is inhibiting CYP3A4, it can’t work as effectively to break down the medications in your system.

The reverse can happen, too. Many medications inhibit CYP3A4. If you then take CBD while on these medications, your body can’t work to process the CBD as effectively.

If your body is metabolizing a medication too slowly, you may have more medication in your system at one time than intended — even if you’ve stuck to your normal dose. An increased level of a medication in your system could exaggerate its effects, including unwanted or harmful side effects.

Some substances also speed up the work of the CYP450 enzyme family. If your body is metabolizing a medication too fast because another substance is inducing the enzymes, you may not have enough of the medication in your system at one time to treat a health issue.

Trying CBD safely while taking medications

If you want to try CBD as an add-on therapy to ease symptoms of a certain condition, talk to your doctor about it first.

They may be able to help determine a CBD product, dosage, and schedule that’s safe with your medications. For some situations, your doctor may want to monitor blood plasma levels of certain medications you take.

Don’t stop any of your medications to try CBD, unless your doctor says it’s safe to do so.

Keep in mind that topical CBD, like lotions, creams, and salves, may also be an option. Unlike oils, edibles, and vaping solutions, topicals don’t typically enter the bloodstream — as long as they’re not a transdermal solution intended to do so.

Look for the grapefruit warning

Although studies are still ongoing to determine potential interactions between CBD and specific medications, there’s one rule of thumb that can help consumers in the meantime: Avoid CBD if your medications have a grapefruit warning on the label.

This warning indicates that people taking the medication should avoid consuming grapefruit or grapefruit juice.

According to the Food and Drug Administration, consuming grapefruit while on one of these medications can lead to a higher concentration of the medication in the bloodstream and adverse side effects or even an overdose.

More than 85 drugs interact with grapefruit and some closely related citrus juices — like Seville oranges, pomelos, and tangelos. That’s because chemicals in grapefruit known as furanocoumarins inhibit CYP3A4, in a similar fashion as CBD. The result is a slowed metabolization of medications.

Grapefruit warnings are common in several types of medications, but not all medications within a category will require the avoidance of grapefruit. Check your medication’s insert information or ask your doctor.

Types of medications that commonly have a grapefruit warning

  • antibiotics and antimicrobials
  • anticancer medications
  • antihistamines
  • antiepileptic drugs (AEDs)
  • blood pressure medications
  • blood thinners
  • cholesterol medications
  • corticosteroids
  • erectile disfunction medications
  • GI medications, such as to treat GERD or nausea
  • heart rhythm medications
  • immunosuppressants
  • mood medications, such as to treat anxiety, depression, or mood disorders
  • pain medications
  • prostate medications

Current research on interactions between CBD and medications

Researchers are working to determine the specific interactions between CBD and various medications. Studies have been done in animals for certain medications, but in many cases, scientists are still determining how those results translate to humans.

Some small clinical trials have been conducted. For example, in one study of 25 children with hard-to-treat epilepsy, 13 kids were given both clobazam and CBD. Researchers found elevated levels of the clobazam in these children. They report that taking CBD and clobazam together is safe, but recommend monitoring medications levels during treatment.

In another study, 39 adults and 42 children taking AEDs were also given CBD in the form of Epidiolex. The CBD doses were increased every 2 weeks.

Researchers monitored the serum levels of the AEDs in subjects over time. While the serum levels remained within the accepted therapeutic range for most of them, two medications — clobazam and desmethylclobazam — had serum levels outside the therapeutic range.

Initial studies show that CBD can definitely mess with medication levels in your system, even if you’re taking your prescribed dosage. But more research is needed to determine the severity of CBD interactions across different medications and to develop recommendations for taking them along with CBD.

Under the careful supervision of your doctor, you might still be able to safely use CBD with medications, even those that have a grapefruit warning.

If necessary, your doctor may monitor plasma serum levels of the medication you’re taking. They may also choose to monitor your liver functioning.

If you’re taking CBD with medications, it’s important to keep an eye out for any potential changes in how the medication or the CBD affects you.

Side effects to watch for

  • increased or new medication side effects, such as:
    • drowsiness
    • sedation
    • nausea
  • a decrease in medication effectiveness, such as:
    • breakthrough seizures
  • common CBD side effects or changes in them, such as:
    • fatigue
    • diarrhea
    • changes in appetite
    • changes in weight

The bottom line is to always consult your doctor first if you’d like to try CBD, especially if you have a health condition and are taking medications. Don’t stop taking your prescription medications to try CBD, unless you have the go-ahead from your doctor.

Medications that come with a grapefruit warning are likely to interact with CBD. However, even if you take one of these medications, your doctor might be able to formulate a plan that works for you through close monitoring of medication levels in your system. That way, you can use both your prescription and CBD as a therapy.

Your doctor or pharmacist may also be able to recommend a quality CBD product that fits your needs. You can also find reputable products with a little research and know-how on reading CBD labels.

Is CBD Legal? Hemp-derived CBD products (with less than 0.3 percent THC) are legal on the federal level, but are still illegal under some state laws. Marijuana-derived CBD products are illegal on the federal level, but are legal under some state laws. Check your state’s laws and those of anywhere you travel. Keep in mind that nonprescription CBD products are not FDA-approved, and may be inaccurately labeled.


Jennifer Chesak is a medical journalist for several national publications, a writing instructor, and a freelance book editor. She earned her Master of Science in journalism from Northwestern’s Medill. She’s also the managing editor for the literary magazine, Shift. Jennifer lives in Nashville but hails from North Dakota, and when she’s not writing or sticking her nose in a book, she’s usually running trails or futzing with her garden. Follow her on Instagram or Twitter.