Does CBD Interact or Interfere with Medication? What Arthritis Patients Must Know Now
If you use CBD products, you need to understand how they could interact with the other medications you take.
CBD (cannabidiol) is seemingly everywhere, with oils, tinctures, pills, chocolates, gummy bears, and creams available all over the internet, at national drugstore chains, and perhaps at your local farmer’s market — even if you don’t live in a state where medical or recreational marijuana is legal.
CBD, a type of chemical known as a cannabinoid, is a mainingredient in hemp, one type of cannabis plant. Marijuana, another type of cannabis plant, also has some CBD but an abundance of THC (tetrahydrocannabinol), an intoxicating cannabinoid known for making users feel “stoned” or “high.” While CBD won’t get you high, it interacts with cannabinoid receptors in your body and may have effects that are sought by people with arthritis, such as pain relief, reduced inflammation, and improvements in sleep and anxiety.
According to CreakyJoints research presented at the 2019 Annual European Congress of Rheumatology meeting earlier this year, 52 percent of respondents reported having tried CBD for a medical reason. Of those who did, 93 percent said it helped. More than half said they wanted more information on CBD from their doctor, but 58 percent of those who told their doctors about their CBD use did not get the information on safety, effectiveness, and dosing they were looking for.
One common concern among people with chronic illness who use CBD is whether CBD can interfere with prescription drugs you may take for arthritis or other conditions.
We put commonly asked questions to Nina M. Bemben, PharmD, BCPS, a specialist in drug interactions who is trying to educate other pharmacists about possible drug-drug interactions with CBD, as well as Rachna Patel, DO, a physician who does consultations about medical marijuana and CBD and sells her own line of CBD products.
What kind of drug interactions can happen with CBD?
A huge number of medications, including CBD, are broken down by the same large family of liver enzymes, called CYP450.
CBD inhibits some enzymes in this family. This makes them break down certain drugs more slowly, which could potentially increase side effects unless your doctor adjusts the dose. On the other hand, CBD induces other enzymes in this family, which speeds the breakdown of certain drugs so they may potentially be less effective unless the dose is increased.
As examples, you may experience increased side effects if CBD is used along with these drugs:
- Antidepressants (such as fluoxetine, or Prozac)
- Medications that can cause drowsiness (antipsychotics, benzodiazepines)
- Macrolide antibiotics (erythromycin, clarithromycin)
- Heart medications (some calcium channel blockers)
“There is still a lot of uncertainty about how CBD interacts with drug-metabolizing enzymes in the body. We know that there are some drug-metabolizing enzymes that are affected by CBD, some that are not, and many others where we just don’t have any information yet,” says Dr. Bemben.
What do we know for sure about CBD’s interactions with other drugs?
The most direct information comes from studies on the only FDA-approved CBD product, Epidiolex, which is used to treat rare forms of epilepsy. Epidiolex has been found to increase blood levels of the blood thinner warfarin about 30 percent, which raises the risk of bleeding. It also interacts with other medications used for epilepsy.
“The manufacturer of Epidiolex was asked by the FDA to conduct more drug-drug interaction studies, so we will learn more about CBD’s interactions with other drugs in the future,” says Dr. Bemben.
Can CBD interact with medications I take specifically for arthritis?
“Based on what we know now about the way CBD is metabolized, I would not expect significant drug-drug interactions with drugs commonly used in arthritis treatment, such as methotrexate, and most nonsteroidal anti-inflammatory drugs (NSAIDs). I would advise caution on one NSAID, diclofenac, because there isn’t information on how CBD affects — if at all — the enzyme that metabolizes it,” says Dr. Bemben.
Rheumatologists are always on the alert for liver problems that may result from arthritis medications, and that includes CBD as well as NSAIDs and methotrexate.
Are older people more at risk of CBD drug interactions?
Yes, for several reasons. “As we age, our livers and kidneys may be slower to eliminate drugs from the body. In addition, older patients and those with chronic health problems are more likely to be using multiple medications, so the risk for drug interactions increases,” says Dr. Bemben.
Dr. Patel worries in particular about any side effects or interactions that result in dizziness and may increase the risk of falls in the elderly. For example, using the antidepressant fluoxetine together with cannabis products can increase dizziness and drowsiness.
Are there some people who should stay away from CBD?
Hold off if you have known liver damage, says Dr. Patel. In a study done on mice published earlier this year, the dose of CBD used to protect against seizures was found to induce liver damage. According to other animal research, CBD may increase levels of liver enzymes, raising concerns about liver toxicity in patients taking methotrexate.
“We use other therapies that cause liver injury, like nonsteroidal anti-inflammatories (NSAIDs). If liver enzymes go up in someone on methotrexate, we would generally hold the drug other than methotrexate [for example, CBD or an NSAID] to see if the enzyme levels normalize,” says Michael Weinblatt, MD, professor of medicine at Harvard Medical School in Boston.
People who take Epidiolex for epilepsy are more likely to develop abnormal liver enzymes, as well as sleepiness and other symptoms, if they are also using valproic acid to control seizures.
“This is important for people with arthritis to know because valproic acid is sometimes used for pain that isn’t controlled by other medications,” says Dr. Patel.
If I stick with a CBD cream, does that reduce the risk of drug interactions?
Probably, since little if any of a topical product is likely to be absorbed into your system. “Unfortunately, we just don’t have good information about how much of a topical CBD product gets absorbed. This can be influenced by the inactive ingredients in the product, where on the body it’s applied, and whether you apply a bandage over the area after applying it,” says Dr. Bemben.
While topical CBD products may not be absorbed deeply enough to raise concerns about drug interactions, that also means they may not be as effective for arthritis pain. “If you just have one joint hurting and it’s close to the surface, using a topical would be appropriate. It’s not as likely to help a hip or other deep joint,” says Dr. Patel.
Which health professionals need to know I’m trying CBD?
Tell your rheumatologist and anyone else who prescribes medication for you. If you need surgery, an anesthesiologist may choose a different dose or type of anesthesia if you’re using CBD.
“If you fill all of your medications at the same pharmacy, your pharmacist will be able to assess for drug interactions for all of them, regardless of who prescribed them. You should still let the pharmacist know about over-the-counter medications, herbs, and supplements — including CBD — that you don’t get through the pharmacy. It is important to bring the CBD product to your doctor and pharmacist so they can check the amount of CBD and other ingredients it contains,” says Dr. Bemben.
“While patients may be wary of stigma surrounding CBD products, I believe most health care providers understand this is a growing area and one strategy patients are trying in hopes of getting relief,” she says.
Is there an online source I can use to figure out which of my medications might interact with CBD?
Online databases are available to help health professionals evaluate potential drug-drug interactions, at a price. “Freely available resources tend to be less reliable, and this highlights the importance of discussing all your medications, including CBD, with your doctor and pharmacist,” says Dr. Bemben.
One source available to patients is drugs.com, where you can plug in either cannabidiol (which will give you the FDA-approved oral product Epidiolex) or cannabis (which will give you both THC and CBD) and check for possible interactions with other medications you take.
Has anyone had a life-threatening drug interaction with CBD?
“There haven’t been reports of serious drug-drug interactions with over-the-counter CBD products. However, these products are relatively new and it typically takes time for reports to be published. We have very little information about over-the-counter CBD products and how they may interact with other drugs,” says Dr. Bemben.
Learn more about CBD interactions with drugs and how to stay safe when you use CBD for pain or other symptoms.
CBD May Possibly Interfere With Your Daily Medication
The interest in cannabidiol (aka CBD ) ― a nonpsychoactive chemical found in marijuana and hemp plants ― is only growing. It has made its way into our shampoos and lotions . There are CBD-infused smoothies, bath bombs and beer. There are even holiday treats (looking at you, CBD jelly beans).
Many people ― including medical experts ― say it’s beneficial in helping to manage different ailments like anxiety , sleeplessness and pain . But while CBD has been advertised as an effective way to treat a wide mix of maladies, the compound is still largely unregulated and unstudied.
“It’s the wild, wild West right now,” said Michelle Henry , a board-certified dermatologist and Harvard-trained Mohs surgeon.
Because of that, there are some questions about how it may impact a user’s life ― specifically if they’re taking drugs for other health issues. Here’s what experts know so far:
Researchers suspect CBD could interact with most medications
Little is known about how CBD could affect other medications a person is taking, according to Yasmin Hurd, a CBD researcher and the director of the Addiction Institute at the Icahn School of Medicine at Mount Sinai. Still, Hurd suspects the substance could very well negatively interact with most medications that are taken orally.
Other experts seem to agree. Nearly 60 percent of the medications on the market are metabolized through a set of liver enzymes — called cytochrome P450, or CYP450 — that are, coincidentally, the same enzymes that break down CBD, Henry explained. Previous research suggests that CBD is a very strong inhibitor of the CYP450 enzymes. This means that if you take CBD while on another medication, it could block these critical enzymes, allowing more of the medication to get into your system.
“So, let’s say you’re on a medication like warfarin or Coumadin, a really common medication we give to a lot of patients to thin their blood,” Henry said. “If [CBD] is blocking the metabolism of warfarin, that warfarin is now higher and more active and can either become toxic or cause other problems.” In the case of a blood thinner like warfarin, “other problems” could entail a traumatic bleed or a dangerous hemorrhage, she added.
The same goes for benzodiazepines (or benzos) like Xanax or Ativan, which are used to treat anxiety. If CBD is taken in conjunction with one of these drugs, it could increase the side effects and potentially cause you to feel more sedated or drowsy. In some rare cases, the drug combo may become toxic or even interfere with your respiratory system, according to Henry. Doctors suspect that certain antibiotics and even NSAIDs (think Aleve or Advil) are altered by CBD consumption as well, Hurd said.
According to the District of Columbia Department of Health , CBD can also increase the serum concentrations ― the amount of medication in your blood ― of a ton of other drugs, including antidepressants, antihistamines, antiretrovirals, calcium channel blockers and beta blockers.
You may have heard of the grapefruit rule , which suggests that the citrus fruit can impair how your body absorbs certain drugs — mainly cholesterol medications, blood pressure drugs and allergy pills. That same mechanism is no different than CBD’s, Harvard Medical School reported . According to Henry, grapefruit inhibits the same set of liver enzymes that CBD blocks. So, like CBD, grapefruit juice can boost levels of other medications in your blood.
How intensely this all plays out in your body mainly depends on the dosage of both the medication and the CBD that you’re taking, Hurd said. “If the concentration of CBD is high enough, it could inhibit the activity of those enzymes, so you would get more of the other drug getting into your system,” she added.
On the flip side, very low amounts of CBD don’t seem to have that much of an effect on how well your body processes other medications. But unfortunately, there hasn’t been enough research to determine how much CBD is considered safe.
Other factors could also influence how CBD does or doesn’t affect your medication
The timing of when you take both the CBD and any other medications can also be a factor in how the drugs may interact in your body.
“Spacing out doses of medicine does help to reduce the workload on the liver,” Hurd explained. “For example, depending on the half-life of a drug, its ability to inhibit liver enzymes might be diminished after a couple of hours depending on dose, etc., thus liver enzymes could regain sufficient function by the time a second drug is consumed later on.”
In other words, the risk of having a serious drug interaction may be lower if you take your medications and CBD at different times of the day.
Finally, everyone responds to drugs differently. Some people may be very sensitive to a particular substance, while others may have little to no reaction. Ultimately, how our bodies process medication ― and the effect it will have ― is heavily influenced by genetics, age and body size.
The form of CBD also matters
The way you use CBD — whether orally, sublingually or topically — also contributes to the interaction with medication. It all boils down to how much of the substance makes its way to the bloodstream, which varies based on the method.
An IV would provide the most direct route, Henry said, as it’s putting the drug right into your blood. Second up is using CBD sublingually — underneath the tongue — or inhaling it, followed by eating (or drinking) CBD.
When ingested, CBD has to go through the gastrointestinal system, which reduces some of the absorption in the bloodstream before it makes its way to the liver where those very important enzymes are.
The least potent route is through the skin. The amount of CBD your body absorbs and sends to the bloodstream through the skin is likely negligible, according to Henry. Therefore, chances are low that you’ll experience any sort of interaction with your medication when using CBD topically, like through a lotion or cream.
The bottom line: You shouldn’t mix without talking to a doctor first
Henry advised to stay away from CBD if you’re taking medications that are metabolized by those same liver enzymes, such as certain anti-anxiety drugs or blood thinners. If you’re unsure, it’s always smart to talk to your physician before throwing CBD into the mix. If you’re set on taking CBD, your doctor may be able to adjust the dose of your other medications. While CBD does seem relatively OK to use ― and many people find it helps with their health concerns ― you just want to be cognizant of any potential health risks.
“I do think that many people think that CBD is benign and it’s safe — and it’s relatively safe compared to so many drugs out there. However, it still has bioactive effects,” Hurd said.
Just like anything else you put in or on your body, it’s best to err on the side of caution and know, to the best of your ability, exactly what the potential side effects are.
Experts share how cannabidiol can impact anxiety medication, blood thinners and even pain relievers.