CBD Oil Drug Interactions

Enzyme Metabolism CBD

CBD Oil drug interactions is a very sensitive and important topic. Dosage and interactions are perhaps the most common question people ask when seeking information regarding Cannabidiol. It’s logic: it’s our health we are talking about, isn’t it?

Potential interactions of CBD with our medications can put your health at risk.

Before you start reading the article, I should remind you that:


(and, frankly, I’ve never wanted to be one!)

My intention is to inform you of the possible ways CBD oil can interact with your medication and to urge you to

Consult Your Physician

before you start using a CBD oil product, if you are currently on any medication.

Now, that my intentions are clear 🙂 let me start by answering your questions.

Are there CBD interactions with other medications?  

The answer is a straightforward yes.

When you take CBD on its own, it can help you treat several health issues. For most people, CBD is a safe supplement to take with rare and mild side effects and without the risk of overdosing.

But when you take other medicines, you should be careful and consider the possible implications, especially if you are taking large doses of CBD.

Even though most of these interactions are often mild and perhaps you wouldn’t even notice them, there are certain drugs that combined with CBD can cause fairly severe contraindications.  

Why is that? What happens inside our body when we combine CBD with those drugs?


Understanding CBD drug interactions

As I’ve explained in a previous article, CBD’s interaction with the  Endocannabinoid System is very important because it affects several functions of our body especially in the neurologic, immunologic and endocrine systems.  

To understand the interactions of CBD with the various drugs we should understand their pharmacokinetics and the way they are metabolized.

What is Pharmacokinetics ?

Pharmacokinetics (from the Greek word pharmakon “drug” and kinetikos “moving, putting in motion”) is a branch of pharmacology dedicated to discovering the fate of substances administered to a living organism. Why is it important in our case?

Simply, because it describes the “trip” of a drug after it has been administered to your body;  how it is absorbed (first step: absorption) and how your body handles it after it has done its work or not! (second step: metabolism); to put it simply, pharmacokinetics informs us of the way the body gets rid of or eliminates absorbed substances from our system.  

The usual way the body detoxifies itself from drugs is by excreting them in the urine or the faeces. In these cases,  there isn’t any interactions issue. But it’s not the only way.

Unfortunately, the pharmacokinetics of both CBD and most of the prescribed medicines isn’t as simple.  

More than half of all pharmaceuticals are not excreted in the urine. They are metabolized in the liver.

CYP450 Pathway

What is the CYP450 pathway?

The majority of medicines – CBD included– is metabolized by a group of specific enzymes called cytochrome P450 (CYP) which are concentrated in the liver and form a metabolic enzyme system that has the role of breaking down drugs.

This system is called CYP450  Pathway and is as unique as each person’s fingerprint and DNA profile.

Why is CYP450 important?

The CYP450 pathway is the metabolic “road”  through which 60% of all pharmaceuticals you consume will travel in your body in order to take effect and to be excreted.

The system is subordinate to the drug you consume. This means that sometimes the process of metabolism is inhibited or speeded up by the drug itself. The behavior of each drug and the way it moves through the system decides both the dosage and its possible contraindications. If you take just one drug, regulating the dose can prevent any undesired side effects.

But what happens when there is a need for more than one drug?

Have you ever wondered why your doctor asks you whether you are taking any other drugs prior to prescribing and dosing a new one? Well, because if you are on a drug that alters the way your body metabolizes other drugs, the combination of the two and the wrong dosage might be fatal.

(To be honest, also a not-so-well liver can be problematic with the functioning of this system and can cause unwanted drug interactions. Drugs need a healthy liver to be metabolized properly, so take care of it! Less alcohol, please! )

How does CBD affect the CYP450 pathway ?

Before I answer this question I want you to try to answer this one :

What is the connection of grapefruit with prescribed medications?

I’m waiting..

Come on, give it a try!


I am a patient person, you know…

But perhaps you aren’t.

So let me explain what the heck grapefruit has to do with prescription drugs.

In 1989, a group of scientists discovered an interaction between grapefruit and certain medications. This interaction enhances systemic drug concentration through impaired drug metabolism. This means that grapefruit, this healthy and “innocent” fruit, is strictly forbidden to be combined with certain medications because some of its compounds impact negatively the CYP450 Pathway by inhibiting the CYP enzymes.

(So, if your doctor ever warns you not to eat grapefruit before taking your drugs, trust him and don’t worry. He isn’t nuts!)

CBD does exactly the same thing. Only…

It’s even stronger than grapefruit!

CBD interacts with CYP450 Pathway in a critical way: they both deactivate each other.

Cannabidiol acts as a competitive inhibitor, meaning that while it is metabolized by the CYT enzymes, it binds to the site of enzymatic activity, it inhibits its chemical competitors and prevents the enzymes from metabolizing other compounds.

In simple words, if you take certain drugs with CBD, the system, obeying to the order taken by cannabidiol, will focus on metabolizing it, “letting loose” the rest of the drugs.

If drugs aren’t metabolized as predicted or properly, they stay in your system longer than they would or should, causing negative side effects and complications. You don’t want that !

Note that not only CBD or grapefruit have this unusual effect on the CYP450 pathway. Watercress, St. John’s Wort and certain foods can cause unwanted drug interactions.

Positive Effects of CBD drug interactions

No, I didn’t make a mistake and yes, you read well.

CBD drug interactions don’t necessarily have to be negative. In some cases, they can be not only good but excellent! CBD can enhance the effectiveness of certain drugs permitting the user to lower his dose and to minimize the possible side effects of these drugs.

In a recent study, CBD was given as a co-medicine to clobazam (an anti-seizure drug) to a group of children suffering from refractory epilepsy. The scientists found that patients had a 70% decrease in seizures and they were able to reduce the clobazam dosage. And this is, certainly, good!!


Negative Effects of CBD drug Interactions

Although the research regarding the subject is still limited,  there is evidence that high doses of CBD may be the cause of high levels of certain pharmaceutical substances in your bloodstream and the intensification of their effects.

CBD Drug Interactions

Now, let’s take a look at the way CBD behaves when it is combined with some drug categories.

CBD and Opioids

In two recent articles of mine regarding athletes that use CBD and especially those involved with American football, I pointed out the opioid addiction epidemic that is taking by storm the sports world.

CBD interacts with the opioid receptors in our brain in a very interesting and, at the same time, important way. It actually stimulates the ECS and modulates the opioid receptors.

The results of this interaction are

  • Increased levels of analgesia.  

What we notice studying CBD in relation to pain and opioid use (and abuse) is that it gives the effect of increased analgesia

  • No respiratory depression
  • Opioid tolerance reduction.

One of the huge problems with opioids is that people that use them to treat chronic pain, get addicted to them quickly. This means that soon they require higher doses of the drug to find relief and get the specific benefits for their ailment. It has been shown that thanks to CBD the opioid tolerance can be decreased up to 75%.

  • Decreased addiction symptoms.
  • Decreased addiction behavior.

As I have already mentioned in my article regarding drug addiction, it has been shown that cravings decrease dramatically with the help of CBD.

CBD and Antidepressants

Antidepressants -including SNRIs (=serotonin and norepinephrine reuptake inhibitors), and SSRIs (=selective serotonin reuptake inhibitors)- are used to treat anxiety and depression. In some cases, however, they seem unable to offer the relief some patients seek.

We know that our Endocannabinoid System is linked to mood and anxiety. CBD, by interacting with the ECS and other areas in the brain, is able to improve the symptoms of depression. A lot of people have experienced an improvement in the symptoms of depression after combining CBD oil with their antidepressant (especially SSRI).

Don’t rush to add CBD to your antidepressant regimen, though. It has the potential to interact with many antidepressants inhibiting their metabolism. Discuss your decision with your doctor!

CBD oil and Antipsychotics

The warning of the US Department of Health regarding the contraindications of cannabis products in patients with acute psychosis or unstable psychiatric conditions isn’t valid for CBD oil because Cannabidiol has no psychoactive properties.

On the contrary, it has been found to decrease symptoms of psychosis.

Yet, CBD oil interacts with antipsychotics by reducing the speed of their elimination from the body.   

CBD and Mood Stabilizers

A common mood stabilizer is Lithium.

Studies have found that CBD may be used by patients with bipolar disorders because it has results comparable to those of lithium. Attention should be paid to marijuana CBD oil products because of their high content in THC which can bring about anxiety and increase the risk for mood swings to patients.  

CBD interacts with mood stabilizers in a similar way as with antidepressants and antipsychotics.

CBD and Benzodiazepines

Both CBD and Benzodiazepines are used by anxiety sufferers to calm their symptoms.

In combination with benzodiazepines, CBD increases sedation and parallel use of the two should be monitored by a specialist.

CBD and Stimulants

CBD with caffeine is a good combination! They collaborate to improve alertness and in the right amounts, they reduce anxiety symptoms.

Increased dosage of CBD, though, can cause sedation and may offset the stimulation caffeine offers to the organism.

CBD and Blood Thinners

A study published in 2017, showed that CBD interacts with blood thinners like warfarin. This means that people on warfarin should be cautious when adding CBD to their pharmaceutical regimen.

When patients take blood thinners and CBD together, the former are subjected to prolonged activity and their effects are enhanced as if they had taken a double dose of the blood thinner.

CBD and Beta-Blockers

Beta-blockers ( Tenormin, Toprol-XL, Sectral, Bystolic, Zebeta) are used to lower blood pressure and slow down the heart rate by inhibiting the effect of epinephrine. CBD may amplify their effects of slowing down the heart.

I could go on examining the interactions of CBD with all drug categories. I don’t want to tire you, so I’ll stop here. You can seek more information according to your personal needs in this downloadable file.

CBD Drug interactions and Administration Mode

The way CBD  is consumed has a significant impact on whether it will interact with other drugs or not.

The interactions are likely when both drugs are administered orally because before their distribution to the organism they will be processed by the liver. So if you ingest CBD -either by sublingual administration or by consuming an edible product -you should know that there will be higher live concentrations and thus the drug interactions will be more potent.

When you vape CBD,  it will pass through the lungs into the bloodstream and arrive at the brain and the heart. Then it will slowly pass through the liver. Inhaled cannabidiol have significantly lower liver concentrations than ingested CBD.

There are no metabolic drug interactions when you administer CBD topically. A CBD salve or body butter is absorbed by the skin and arrives at the joints, but it never gets into the bloodstream.

Administration Mode

CBD Drug Interactions and Administration Sequence

You should know that cannabidiol is absorbed more when it is ingested on a full stomach but the process of absorption is slower.  The time it needs to get to the liver, be processed and enter the bloodstream, ranges from 2 to 4 hours.

When you take CBD sublingually, it isn’t immediately processed by the liver and it doesn’t go directly to your brain and heart. It enters your bloodstream in, around, 15 minutes.

On the other hand, tinctures need around 2 hours.

A study found that CBD’s inhibitory impact on a certain enzyme of the cytochrome P450 family is significantly stronger if cannabidiol is taken 20 minutes before the administration of the second drug.

How to use CBD safely

I truly hope that my article didn’t make you anxious or afraid.

Its aim was to inform you of the interactions -positive and negative -CBD can have with other drugs and not to create any panic or anti-cannabis hysteria. We have had enough of misleading propaganda and cannabis “witch hunt” in the past.

Is the combination of CBD with other drugs dangerous? It is as dangerous as taking an incorrect dose of your mainstream drug or combining two drugs that shouldn’t be combined.

The drug interaction issue is not something new. It is responsible for about 100 thousand deaths,  2.2 million hospitalizations and $130 billion spent per year only in the US. And, you know what? CBD isn’t, at all, responsible for these numbers.

When it comes to drugs we, all, depend on our doctors.

What should you do?

The grapefruit test is a good indicator of the possible interactions, but I strongly advise you to consult your physician.

If you are not taking any drugs, then don’t hesitate to use CBD. It’s a safe, natural supplement that can boost your immune system and overall health.

If you are on CBD and your doctor has to prescribe you a pharmaceutical medication for some reason, don’t forget to inform him that you take CBD oil.

If you are on any pharmaceutical substance, it is crucial that you consult your doctor about the potential interactions of your medicine with CBD in case you want to start using it. He will give you advice on dosage and sequence and will help you avoid undesirable interactions.

Remember :

When it comes to health issues and medicines, OUR BEST FRIEND IS OUR TRUSTED DOCTOR.

Patient Doctor


If you have any questions or you want to share your personal experience with CBD and/or any drug interactions, leave a comment below.

If you want to know if I have published a new article, or get information about CBD news, product releases or promotions, don’t hesitate to sign up for my email list!

DISCLAIMER: The content of this article is for informational purposes only. It is not meant to substitute professional medical advice, diagnosis or treatment. The information provided is not meant to alleviate or cure any disease or disorder. Always seek the advice of a qualified health provider for any medical condition.


  1. It’s amazing to read how CBD can help solve the opiod epidemic. It’s been growing for years now, especially in the portion of the US that I live in and the fact it both athletes and everyday people who use CBD on a consistent basis see the urge to use opiods decrease in both addiction behavior and symptoms intrigues me.

    I wish the mainstream would jump on board with this, especially as they continually add fuel to the opiod addiction fire on a weekly basis, at least where I’m from. The fact we might have a remedy should be newsworthy. I was glad to read this part of the article.

    1. Will big pharma industry behind opioids permit it, Todd? That’s the big question. They will lose billions if people turn to a natural remedy like CBD oil and substitute opioids. I don’t see any negative moves perhaps because it’s too soon and their earnings haven’t been influenced yet. I like to think pink but I am not very optimistic regarding their future reaction.

  2. Wonderful information! I learned some here for sure. I had not heard about grapefruit, perhaps I have just never taken a medication that would adversely react with it. I recently started taking a mild antidepressant for what my doctor calls “situational depression”. So now I am thinking that I can take CBD oil as well, and hopefully feel like a complete person again! Thanks for the great information.

    1. I wonder why you chose to take the medicine. You could give your son’s CBD a try. I managed to overcome my sleep problems and my “situational depression” with it. If you want to use both, please consult your physician, Leahrae.Promise?

  3. My understanding was that medicine can be taken with any fruit juice including grapefruit. So it comes as a surprise to me it can affect the CYP450 pathway. But I have taken the lesson.
    The combination I have liked is one of CBD with caffeine that improves alertness. This is what I need with the things I am doing.
    This is another great post from you Effie.

    1. I like the coffee-CBD combination too, Ahimbe. It helps me a lot. You are right, it’s pretty interesting that grapefruit can interact with the CYP450 pathway. Same as CBD.So be careful! The human body will never stop amazing us, don’t you think?

  4. Very enlightening information. I do take a few prescriptions, none that you have listed here. I will have to do some more research as I do not have any reactions at this time.
    I am glad that I found your information so that I can understand more about the good and bad of CBD oil and its reaction to other medications.
    I normally take my daily dose of CBD oil in the morning and my medication in the evening before bed, do you think that this will diminish the effects on the oil and medication.

  5. Very interesting Effie! Luckily I don’t take any prescription medications but I didn’t realize that there were potentially any interactions. Interesting that most of the interactions show up with pharmaceutical drugs. I have never had any negative interactions or side effects since I started taking it. Only good ones. Even with the potential for interactions, I think CBD oil is still very safe when you consider everything. Great post!

    1. If grapefruit can interact with drugs, it’s no surprise that CBD might do too, right? I didn’t have any side effects either but every individual has his unique biochemistry, unique as his fingerprints and his body can react differently. And, yes, you are right, compared to all the chemical junk we put in our body, CBD is one of the safest solutions to our issues

  6. Thank you for this thorough article about CBD and its interactions with other medications. I really believe that giving patients or any individual proper and thorough explanations is very important to prevent untoward reactions.

    Here in the States the rate of opioid dependence among individuals are increasing, I wish there will be more doctors especially Pain management doctors that will be more open to CBD. Depression is also on the rise so instead of taking anti depressant in the form of pills, CBD might just be the answer. But there’s no harm in asking our trusted doctors so I will suggest this to a friend who has depression.

    1. Thank you for stopping by and commenting Nida. Your professional experience and opinion are valuable to me! You are right: CBD may be the answer to many problems. Let us hope that doctors will be more open to it in the future

  7. I’ve known about the potential for grapefruit to enhance the potency of certain prescription medications but I never truly understood the mechanism. Thanks for sharing that.

    In fact, this whole piece does a valuable public service well beyond the specific subject at hand. I think people really need to take care when it comes to combining drugs of any kind.

    I had an elderly neighbor who nearly died because none of her doctors talked to each other. She had been given one prescription after another and ended up on a number of different drugs, many of which did not play well together. It took about a week for them to finally figure it out.

    Very helpful, responsible article, thank you.

    1. Your neighbor’s “adventure” was as shocking as the statistics regarding drug interactions. Doctors are the experts when it comes to drugs and they must protect their patients from the potential risk of combining different drugs. I hope all ended well for her!

  8. My Mom is on CBD oil from Marijuana, prescribed by a doctor. I learned recently that she is taking another drug from time to time, that I suspect is being amplified by the CBD oil. The other drug, Valium, she has been using on and off for many years. I am not sure she was upfront about this with the cannabis doctor she went to see. I am going to look into this more. She sleeps more than she should these days, especially during the day. Thanks for your indepth article!

    1. Welcome to my website Madeleine! I appreciate the visit and the comment. You should definitely look into the situation more. Please inform your mother’s doctor that she is on Valium because CBD and Valium interact. He will give you advice and instructions. Thank you for sharing with us 🙂

  9. There’s so much great information in this article!

    I rarely take prescription drugs; my drugs of choice are dark chocolate and coffee. Between the two of them, they fix everything but the pain from osteoarthritis. I’ll be adding CBD oil for that. I’m happy to know that it combines well with caffeine! I will add CBD oil slowly and monitor the results so that I offset anxiety but don’t lose the stimulation from caffeine.

    Although the information about drug interaction does not apply to me directly, I have family members on medications so I may need to print and share this article with them. I’m glad you addressed antidepressants because CBD oil is often recommended to people with depression and I have been wondering about that.

    Thank you for the information! I know that people probably think I’m overly cautious but I really like to know what I’m putting into my body. It took many years to realize I was harming myself with the types of food I was eating and I don’t want to make the same mistakes with supplements and other “beneficial” additions to my diet.

    1. No, you are not overly cautious Theresa. You are reasonably cautious. It’s not only a right but an obligation towards yourself to know what you are putting into your body. I am glad you find my article informing and helpful. A comment of yours was the source of inspiration to write it, so you are definitely responsible for it! Thank you!!

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