Are There Possible Drug Interactions / Conflicts with CBD Oil?

Published on June 12th, 2019

Last updated on June 21st, 2019

Nearly all drugs can have an impact on other medications. So it’s incredibly important to understand how CBD might affect your system.

People often ask us if CBD has any drug interactions. In fact, it may be the most common question we get, and for a good reason. The fact of the matter is that almost every drug imaginable has some sort of impact on other medications. So while CBD is a relatively innocuous substance, it does have an effect on some types of medication.

The primary way in which two drugs usually interact is suppressive or additive. They can even be what is known as synergistic, where the combination of different medications creates an effect much more significant than either would alone.

For these reasons, it’s crucial to consult your doctor before adding any medication to your routine, or else risking severe issues.

As mentioned, the interaction of CBD tends to be quite mild and rare. But that doesn’t mean there aren’t several situations in which you must exercise caution. We’ll briefly discuss how and why CBD impacts certain types of medication, before going over the main culprits of CBD interaction.

While we’re always happy to provide people with the information they’re looking for, it’s vital to discuss any medication decisions with your doctor first.

How CBD Affects Medication

One of the main ways we know the CBD affects other medications is by inhibiting the activation of the enzyme cytochrome P450, via the Endocannabinoid system. By interacting with this enzyme, CBD is known to either reduce or increase the power of certain types of drugs.

The main job of Cytochrome P450, which is found in the liver, is to break down any drugs or toxins present. By inhibiting this, CBD can alter the way some drugs are processed in a significant way.

While it may seem like a big deal, other more common substances are linked to many more severe side-effects. For instance, caffeine has 82 known drug interactions, of which at least 25 are considered severe. CBD, on the other hand, is only known to affect a few main categories.

So let’s go over the most common drug interactions of CBD.

CBD And Sedatives

CBD, as well as THC, have both been known for years to provide some level of sedative-like effect on the user. While both substances are known to have sedative-like effects, they manifest quite differently in the body; THC causes sleepiness, while CBD promotes wakefulness.

The result is that CBD and most sedatives have an additive effect on each other, increasing the impact. No research directly connects CBD and sedative use in a negative light, but not enough is currently known about the potential implications for most experts to suggest combining CBD with sedatives.

CBD And Blood Thinners

Interestingly, researchers believe the effect of CBD on the body is actually closest to grapefruit of all things. You see, both substances suppress Cytochrome P450, which has a significant impact on blood thinners.

Researchers believe CBD and grapefruit both dramatically increase the duration and strength of drugs designed to thin the blood, as well as medications which present the risk for thinned blood, such as ibuprofen.

That’s why it’s strongly suggested you only use CBD and blood thinners at the same time if you’ve discussed it with your doctor, and they plan on tracking your levels

CBD And Chemotherapy

One of the lesser known drug interactions of CBD is with chemotherapy drugs. The fact is, treating cancer with chemotherapy requires very precise and controlled dosages. Too little won’t do anything positive for the patient, and too much could be even more dangerous than the cancer.

As such, many drugs used in chemotherapy are designed to be metabolized at explicitly the right rate. As we’ve established, CBD can have a moderate to severe impact on how many drugs are metabolized, which can result in incorrect dosages.

It’s even more important for this drug interaction to be discussed since cannabis is seen as an effective treatment for the pain and anxiety related to cancer. So it’s essential for your doctor to be aware of how much, if any, you’re taking.

CBD And Anti-Seizure Medication

This last entry is an especially important case because so many people are already aware of the benefits CBD provides those suffering from seizures. However, a study by the respected doctor, Lester Bornheim concluded lower doses of CBD don’t have a beneficial impact on seizures.

Making matters much worse, the same report found small doses still inhibit the cytochrome p450 enzymes, resulting in more significant concentrations of two substances known to cause much more severe seizures, clobazam, and norclobazam.

This perfectly highlights why it’s so important to consult your doctor before making any medication decisions. Even something which is known to help can make things worse if not taken the proper way.


CBD provides a wide array of benefits to people suffering. That said, it’s not a miracle drug, and you have to take caution when using it, just like anything else. That’s why it’s so important you only start a regimen of CBD if you’ve already talked about it with your doctor.

The listed types of medication are far from the only ones that are impacted by CBD, but they do cover the vast majority of samples.

However, if you’re interested in a more comprehensive list of medications you shouldn’t take when starting CBD, just remember that grapefruit and CBD inhibit the same enzyme and therefore cause the same reactions in virtually all cases. This effect of grapefruit is so well known that many affected medications already clearly advise against it. So when in doubt, look for warnings against grapefruit; Who would have thought?

We hope this article helped answer any questions you may have had. Be sure to share it with anyone else who is struggling with the same concerns. If you have any questions or comments, feel free to leave them below or online at Facebook or Twitter.

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