CBD can change the way your body processes certain medications
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.
Research has begun to demonstrate that cannabidiol (CBD) has the potential to effectively help a large number of people. CBD oil interacts with the endocannabinoid system in a way that produces very few unintended side-effects.
While the majority of the vast majority of the science indicates CBD oil is safe for use and consumption, it does pose a few risks that, if not properly understood, could be dangerous.
One of these risks is the inhibition of the cytochrome P450 enzyme system.
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. 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 given to a lot of patients to thin their blood. 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.
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. Doctors suspect that certain antibiotics and even NSAIDs (think Aleve or Advil) are altered by CBD consumption as well.
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, antiretroviral, calcium channel blockers and beta blockers.
What is the Cytochrome P-450 System?
Found within the liver, the cytochrome P450 enzyme system is responsible for metabolizing potentially toxic compounds, including over 60% percent of any drugs you have consumed.
According to Davis’s Drug Guide, this system contains more than 50 enzymes that process and eliminate toxins.
Why Does CYP450 Matter?
In order to determine the appropriate dosages of medications, doctors make calculations using the average amount of time it takes for various drugs and medications to be processed through the cytochrome P450 system.
If only one drug is being processed, and the system is generally healthy, these averages provide accurate dosage information.
However, certain substances have the ability to affect processing times within this system, making drugs metabolize faster or slower than they would on their own.
Similarly, if the cytochrome P450 system is unhealthy due to problems with the liver or other pre-existing conditions, drugs may not metabolize as they should.
Cannabidiol in the Cytochrome P-450 System
Cannabidiol can inhibit the cytochrome P450 system’s ability to metabolize certain drugs, leading to an overall increase in processing times.
Interestingly, CBD oil is not alone in its effect on drug metabolism. Grapefruit, watercress, St. John’s Wort, and goldenseal all have a similar impact in terms of CYP450 inhibition.
If you are taking a medication affected by cannabidiol, you should consult your doctor to make sure that it is safe for you to supplement your personal care routine with CBD oil. From there, the two of you may consider adjusting the dosage on your medications so that you can use both products safely.
Drugs that Interact with Cannabidiol
Any drug metabolized by CYP450 enzymes could potentially interact with cannabidiol. According to the Indiana University Department of Medicine, drugs known to use the CYP450 system include:
- HMG CoA reductase inhibitors
- Calcium channel blockers
- HIV antivirals
- Immune modulators
- Beta blockers
- Angiotension II blockers
- Oral hypoglycemic agents
This list does not include all of the potential medications impacted by cannabidiol. Nor will every medication in the categories contained on this list will cause an interaction. For these reasons, you should consult with a medical professional before supplementing with CBD oil.
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. 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 as it’s putting the drug right into your blood, but of course this is not practical or safe for people at home. 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. 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.
Combining Alcohol and CBD Oil
Alcohol and cannabis are both widely consumed in our society and the effects of combining the two are well known.
What is less understood by the general public, is the effects of combining alcohol and the cannabinoid compound CBD.
Alcohol depends on a few different metabolic pathways in the human body, with the primary enzymes involved being:
- Alcohol dehydrogenase (ADH)
- Aldehyde dehydrogenase (ALDH)
- CYP450 (specifically CYP2E1)
In people who only drink socially or occasionally, ADH and ALDH handle the entire workload of metabolizing ethanol. However, when binge drinking (or during chronic consumption of alcohol) CYP450 gets involved to assist the overloaded ADH and ALDH pathways.
Here are some interesting tidbits about alcohol and CBD oil:
- The CB1 receptor is a significant player in the reinforcing and motivating attributes of alcohol.
- Combining alcohol and CBD results in significantly lower blood levels of alcohol.
- CBD reduces the reinforcement, motivation and relapse for alcohol.
- CBD protects the liver from damage done by binge-drinking alcohol.
- CBD prevents against alcohol-induced neurodegeneration.
- CBD attenuates alcohol-induced liver steatosis, metabolic dysregulation, inflammation and neutrophil-mediated injury.
- Cannabinoids have an effect on nearly all enzymes responsible for metabolizing alcohol.
- CB1 receptor agonists (THC) encourage alcohol consumption, while CB1 receptor antagonists (CBD) decrease it.
Although the pharmacokinetics of alcohol and CBD are not yet well-understood, what we do know is CBD inhibits the CYP450 enzyme system, and this system plays a significant role in alcohol metabolism.
The bottom line: You shouldn’t mix without talking to a doctor first
It’s 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.
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.