There is a lot that’s still unknown about CBD, but some research indicates there are CBD drug interactions with certain prescriptions, like tacrolimus. There’s reason to believe that, as safe as CBD has been shown when used alone, it may have the potential to negatively react with other medications to create some unintended side effects.
CBD drug interactions: Is CBD safe to take with prescription medications?
If you’ve visited a store that sells health and beauty products lately, you may have noticed that products containing CBD, or cannabidiol, seem to be all the rage. Oil, chocolate, supplements, even carbonated beverages, are filling up shelves—enticing shoppers with claims that using one of these products will cure insomnia, alleviate anxiety, reduce inflammation, or treat PTSD.
And shoppers are buying it, so to speak—one recent report indicated that CBD sales are expected to hit $16 billion by 2026, up from just over $1 billion in 2018. But what exactly is CBD, and is it safe for people who are using prescription medications? Before using it, it’s important to learn about the potential CBD drug interactions.
Is CBD marijuana?
While CBD is one of the active ingredients in marijuana, using CBD itself will not get you high (the component that does that is called tetrahydrocannabinol, or THC). CBD is really just a molecule within the hemp variety of the cannabis plant, and there is at least some anecdotal evidence and preliminary research suggesting that the extraction created from this molecule has some health benefits.
CBD is thought to act on certain receptors in your brain and other parts of the body, in ways that could relieve pain, or help certain health conditions, like childhood seizure disorders. However, as with any “natural” product, the fact that it comes from plants doesn’t automatically render it innocuous. For some people, particularly those taking certain prescription medications, using CBD is risky. It has anticoagulant effects that can thin blood; it can also modestly lower blood pressure. These effects could be dangerous for people with certain medical conditions.
“Herbal products are drugs,” says Rita Alloway, Pharm.D. , research professor of nephrology at the University of Cincinnati College of Medicine. “Just because [something] is herbal … doesn’t mean it can’t interact with any of the pharmaceutically manufactured drugs that you may be taking.”
Does CBD interact with medications?
Case in point: tacrolimus , an immunosuppressive medication used to prevent organ rejection in patients who have had heart, liver, or kidney transplants. CBD interferes with the metabolism of tacrolimus, according to research conducted by Dr. Alloway , who specializes in post-transplant immunosuppression. And because tacrolimus is a narrow therapeutic index drug (meaning the window between efficacy and toxicity is very small), this interference can lead to clinically significant negative outcomes (such as kidney problems or organ rejection), she says.
Are the concentrations in commercially available CBD high enough to cause this interaction? The evidence doesn’t really say one way or another. Dr. Alloway’s research involved a high dosage of CBD that wouldn’t be found in a retail product. However, it “highlights that a drug interaction is there,” she says. Plus, tacrolimus is metabolized in the body by a group of enzymes called cytochrome P450 and CBD is a known inhibitor of this process. What does that mean? If CBD inhibits the metabolism of tacrolimus, the patient can end up with too-high levels of tacrolimus in the body. In light of this, she urges anyone taking tacrolimus to speak with their transplant team before using CBD. Don’t get your hopes up, though—using herbal remedies, particularly those with potential interactions, is generally frowned upon by doctors looking after transplant recipients (including Dr. Alloway).
As for other drugs, well, most haven’t been studied yet. There is preliminary evidence that CBD could have a similar effect to grapefruit juice, impairing how your body metabolizes drugs, and raising serum levels of those medications in your body. And, because cytochrome P450 is responsible for the metabolism of numerous medications , proceed with caution before mixing any prescription pharmaceutical with CBD, Dr. Alloway says.
How about CBD’s therapeutic benefits?
Despite the not-so-great news about CBD for patients using tacrolimus, for some people, CBD is actually life-changing in a positive way. In 2018, for example, the CBD-derived medication Epidiolex received FDA approval for the treatment of Lennox-Gastaut syndrome and Dravet syndrome, two very rare and very severe forms of epilepsy.
But claims that CBD aids in the treatment of certain mental health and psychiatric conditions, don’t pass muster, says Roger McIntyre, MD , professor of psychiatry and pharmacology at the University of Toronto.
“There is no role right now for CBD in managing mental disorders that I [treat], such as depression, bipolar disorder … anxiety and ADHD,” he says. “We just don’t have the evidence that supports [it].”
Furthermore, most prescription medications used to manage these conditions are metabolized by cytochrome P450, making it entirely possible that CBD could interfere with—rather than enhance—treatment.
Dr. McIntrye, who co-authored a 2018 study that concluded that healthcare providers need more information about drug-drug interactions with CBD and psychotropic medication, says much of the information out there is confusing and contradictory. Therefore, he echoes Dr. Alloway’s statement that it is absolutely prudent that patients clear the use of CBD with their doctor before giving it a go.
“[The provider] knows the individual and knows what other treatments they may or may not be taking,” Dr. McIntyre explains. “They have a panoramic view of the patient’s medications, and would have [a better idea] of whether the patient is taking another medication that may have an interaction.”
What Kind of Drug Interactions Can Happen with CBD?
Many consumers are increasingly turning to CBD products as a natural alternative to everything from chronic pain relief to the treatment of ADHD, anxiety, and more. While CBD, one of the many compounds inherent to the cannabis sativa plant, may offer a nice alternative to current treatments, including prescription drugs, it’s important to be smart about how CBD could potentially interact with any other medications you’re taking.
7 Common CBD Oil Drug Interactions
- Antidepressants, such as Fluoxetine or Prozac
- Any drug that causes drowsiness, including antipsychotics and benzodiazepines
- Macrolide antibiotics like Erythromycin and Clarithromycin
- Seizure Medications Like Clobazam, Lamotrigine and Vaproate
CBD has many exciting possibilities when it comes to therapeutic treatment, but it’s important to remember that the research around is in the very early stages. Because researchers haven’t fully explored CBD’s mechanism of action (yet), it can be sometimes be hard to predict whether it will have interactions with other medications, both over-the-counter and prescriptions. What behaves as a safe and natural remedy for one patient could have unintended negative interactions with another patient, depending on the other compounds in the patient’s system.
While we’ll outline some of the most common CBD oil drug interactions, it’s always important to visit with your doctor or consult with a pharmacist if you have any concerns about potential negative side effects.
Does CBD Interact with Medications?
There’s reason to believe that, as safe as CBD has been shown when used alone, it may have the potential to negatively react with other medications to create some unintended side effects.
CBD may at times react with over-the-counter medications, herbal products, and some prescription medications, which underscores the necessity of talking with a doctor or pharmacist before trying CBD products if you’re regularly taking a drug for a heart condition, pain or another medical condition. Some medications should never be taken with CBD, while others can be modified or reduced in order to decrease the chance of a negative CBD drug interaction. And while CBD information for medical professionals is in early phases, your doctor is still the best equipped to provide sound advice about how to safely use CBD for your particular medical condition.
According to Nina M. Bemben, PharmD, BCPS —a specialist in drug interactions—CBD, along with many other medications and compounds, are broken down for the body’s use by the liver enzyme family known as Cytochrome p450. Because CBD acts as an inhibitor to certain CYP enzymes, it could cause other medications in the body to be broken down more slowly—which, unless your doctor lowers your dosage, could lead to increased side effects. On the other hand, CBD can induce other CYP enzymes, which may lead to a faster drug metabolism, resulting in reduced efficacy unless the dosage is increased.
While much research is needed on exactly how CBD behaves within our bodies and how it interacts with various other medications, here’s a good general rule to remember: if you take a drug with a label that features a grapefruit juice warning, it’s a good idea to steer clear of any CBD product while you take that drug. Why? According to the U.S. Food and Drug Administration , a medication with this warning, taken together with grapefruit or grapefruit juice, can manifest at a higher than intended concentration within the blood, potentially causing adverse events.
What does this have to do with CBD? A class of chemicals present in grapefruit juice, known as furanocoumarins, inhibit the enzyme CYP3A4—in much the same way CBD does, resulting in a slower metabolization of medications. So, if you’re taking a medication that features a grapefruit warning, there’s a good chance CBD may cause a few issues with that drug as well. More than 85 different drugs react negatively with grapefruit, including many of the following—you’ll notice a distinct overlap between this list and the list of drugs that commonly have a CBD drug interaction:
- Antibiotics and antimicrobials
- Anticancer medications
- Antiepileptic drugs
- Blood pressure medications
- Blood thinners
- Cholesterol medications
- Erectile dysfunction medications
- GI medications, such as those used to treat nausea and GERD
- Heart rhythm medications
- Mental health medications, such as to treat anxiety, depression, or mood disorders
- Pain management medications
- Prostate medications
The good news? Based on what we know about how CBD is metabolized, there doesn’t seem to be much concern over potential reactions to nonsteroidal anti-inflammatory drugs and/or other prescription medications used to treat the symptoms of arthritis. More good news: there are no reports of any life-threatening interactions that over-the-counter CBD products have had with any herbal, OTC, or prescription drug. Commonly reported side effects have included drowsiness, nausea, diarrhea, dry mouth, a decrease in medication efficacy and changes in appetite or weight.
With the help of your doctor, it’s possible to add CBD to your therapeutic regimen, even if you’re taking another prescription medication that could interact negatively with CBD. It may just be a question of adjusting dosage, monitoring liver function and/or carefully watching for side effects.
We also want to stress that you should never forego your current medication to try CBD without talking with your doctor first. Some medications will need the dosage slowly tapered down in order to safely discontinue use, while others may require careful monitoring.
7 Common CBD Oil Drug Interactions
Let’s take a closer look at common medications CBD oil may negatively interact with:
1. Antidepressants, such as Fluoxetine or Prozac
Some common medications prescribed for depression, such as Fluoxetine and Prozac, when combined with CBD, may increase drowsiness or dizziness. This can be dangerous for patients who are older or who otherwise experience mobility issues, as it may increase the chances for a dangerous or even life-threatening fall.
2. Any drug that causes drowsiness, including antipsychotics and benzodiazepines
Any drug that causes drowsiness, which is a surprisingly large collection, has the potential to combine with CBD for an intensified effect. Anyone who is taking these types of medications combined with CBD is at an increased risk for impaired judgment, falls, and other dangerous situations that result from excessive drowsiness.
3. Warfarin and Clopidogrel
Warfarin is a fairly common drug prescribed as a blood thinner. The most reliable information we have about CBD’s potential interaction with Warfarin comes from studies of the only FDA-approved CBD product, Epidiolex, which is a prescription treatment for rare forms of epilepsy. Epidiolex has been shown to increase blood levels of Warfarin by approximately 30 percent. With this increase comes a higher risk of excessive bleeding. Clopidogrel also interacts with CBD.
4. Macrolide antibiotics like Erythromycin and Clarithromycin
These types of antibiotics are widely prescribed for the treatment of bacterial infections. Because CBD has the ability to slow down or speed up the metabolism of antibiotics by our CPY450 enzymes, taking antibiotics in conjunction with CBD may mean you end up with a higher dose of drugs in your system than is either safe or effective.
Amiodarone is often prescribed to address irregular heart rhythm. CBD metabolism often is slowed down when taken in combination with Amiodarone, resulting in elevated levels of both medications in your system if they’re used together. In addition, both CBD and amiodarone can cause an elevation in liver enzymes, and the effect is exacerbated when the two are taken together.
Levothyroxine is a commonly prescribed thyroid medication. In fact, it is likely the most popular drug prescribed for thyroid issues. When CBD and levothyroxine are taken together, they are forced to compete within the CPY450 enzyme pathways for effective drug metabolism. This kind of drug interaction could cause thyroxine to accumulate, which could result in hyperthyroidism. In addition, when thyroid medications and CBD products are taken too closely together, some patients may experience short-term anxiety and mild nausea.
Seizure medications, like Clobazam, Lamotrigine and Vaproate
Clobazam, Lamotrigine, and Vaproate often are prescribed for patients experiencing seizures, either due to epilepsy or other health conditions. In some cases, CBD has increased the Clobazam levels of children treated with both Clobazam and CBD for epilepsy.
Does CBD Consumption Method Matter?
The manner in which you consume CBD absolutely has an effect on its potential to negatively react with other medications you take. Inhaling CBD, for example, deposits the compound almost immediately into your bloodstream, which allows it to reach peak concentration within 30 minutes. This delivery method avoids the liver’s metabolism, but may still increase the chances that CBD will negatively react with other medications already in your system.
Edible CBD vehicles, like soft chews, CBD gummies, etc., take longer to absorb and reach peak concentration, but they also have the potential to reach a highly concentrated enough level that negative interactions are possible. The same is true for a CBD oil or emulsion tincture .
CBD topicals, such as balms, creams, CBD lotion, etc., are the least likely to react negatively with other medications in your bloodstream because absorption through the skin decreases the amount of CBD that may eventually make its way into your bloodstream.
Other factors that influence both the occurrence and severity of a CBD interaction with other pharmaceutical drugs may include the age of the patient, the dosage amount of both CBD, and the interacting drug, plus any existing underlying medical conditions. Older patients may be at higher risk of potential negative drug interaction for a couple of reasons: first, as we age, the time our bodies take to process compounds like CBD and other medications increases, and second, older patients are more likely to take multiple medications on a regular basis.
Your doctor can help you figure out what type of CBD and dosage may be right for you, considering your medical profile and any medications you already take on a regular basis.
Create a CBD Treatment Plan with Your Medical Team Today!
CBD shows great promise in being able to offer patients relief from a wide variety of medical conditions, but it’s still in the early stages of research. If you want to try CBD, but are already taking a medication to treat your condition, make sure to confer with your doctor before adding CBD to your treatment plan or before using CBD to replace any of your current medications.
Your doctor can help you develop a plan that will let you enjoy the highest therapeutic effect of CBD with the fewest possible side effects. And when you’re ready to purchase high quality, responsible CBD products, our team at Farmer & Chemist is here to help—we have a broad variety of CBD oils, creams, gummies, and more. Our team of pharmacists and pharmacy technicians are also available to answer any questions you may have about the appropriate use of CBD, as well as any potential drug interaction you need to speak to your doctor about.