For those considering using medical marijuana that are already on other prescriptions medications, this is a huge concern.

So, I’m going to do a deep-dive into this topic with you – by starting with the basics.


What is Cytochrome (CYP) P450?

When we’re talking about any adverse drug-to-drug interactions, one of the key players is Cytochrome P450.  It’s like a demolition company in our bodies.  It’s just is to take drugs part.  And, it’s responsible for breaking down 60% of prescription drugs that enter our bodies.

CYP can be made to work quicker or slower by other drugs, foods, or substances that you consume.

Let me walk you through a couple examples.

Let’s take grapefruit juice.  Grapefruit juice is an inhibitor of Cytochrome P450. In other words, it slows Cytochrome P450 down.  So, say you downed some medication with some grapefruit juice, it’s likely that Cytochrome P450 will work as slow as molasses in breaking down that medication.  So, grapefruit juice puts CYP in vacation mode.

Now, let’s take tobacco.  Tobacco is a Cytochrome P450 inducer.  In other words, it makes Cytochrome P450 work really, really fast.  So if you had some medication and then decided to go out for a smoke, it’s likely that Cytochrome P450 will have that medication broken down in no time.  So, tobacco makes Cytochrome P450 hyperproductive.

When Cytochrome P450 works too slowly or too quickly, it’s no bueno.  It can cause problems.  The levels of the medication you take could become toxic or, the opposite, they become completely ineffective.

So, now that you know the basics about Cytochrome P450, I want to move on to talk about how marijuana affects Cytochrome P450.  I’m going to focus on the 2 cannabinoids that marijuana makes in the greatest abundance.  And, those are Cannabidiol (CBD) and Tetrahydrocannabinol (THC).



Research in animal models and in test tubes has shown that both CBD and THC slow Cytochrome P450 down. Between CBD and THC, CBD was found to have a greater impact on slowing down CYP than THC.  Specifically, the way in which CBD slows down CYP is that it blocks the breakdown of prescription medications.  Researchers did find that it typically took really high concentrations of CBD to actually slow down Cytochrome P450.




So, there has been some research done on this topic in humans as well.  They’ve been studies done using some very
specific prescribed medications.

Cannabidiol (CBD) and CLOBAZAM

One study looked at the effects of CBD on an anti-seizure medication called Clobazam.  They looked to see what happened when 13 kids with Epilepsy were given Clobazam with CBD.  They basically found that CBD led to less break-down of Clobazam.  Basically, it stuck around longer than normal.  And, as a result, the doses of Clobazam that these kids were on had to be reduced.  And, in turn, the kids experienced fewer side effects of the Clobazam.

Cannabidiol (CBD) and HEXOBARBITAL

Another study looked at the effects of CBD on a medication called Hexobarbital.  It’s a medication that was used back in the 1940’s and 1950’s as anesthesia, but isn’t really used anymore.  The results of the study showed that, again, CBD led to less of break-down of Hexobarbital.  So, basically it also stuck around longer.


And, you’re probably wondering, what does this mean for me, the patient that’s using medical marijuana?

In theory, taking medical marijuana with your prescription medications should impact the breakdown of the prescription medications that you’re taking, but, in general, clinically, this hasn’t really been the case.
So, there’s been a decent amount of research done using marijuana.  And, a lot of the participants continued to take their prescription medications while participating in the study.  So, basically, they were using marijuana along with their prescription medications for conditions like,

Neuropathic Pain
Cancer-Related Pain
Multiple Sclerosis

Overall, the participants of these studies didn’t report any adverse drug-to-drug interactions nor did the researchers observe any adverse drug-to-drug interactions.


Marijuana and Interactions with Other Medications: IN PRACTICE

I’ve been treating patients with medical marijuana since 2012, and in that time I haven’t had any patients report any adverse drug-to-drug interactions either nor have I observed any general trends with adverse drug-to-drug interactions.

Of course, we need more information by way of research, but so far this is what we know and what I’ve seen in my medical marijuana practice.

So there you have it – everything you wanted to know about using medical marijuana and interactions with your prescriptions medications.

As always, I hope you found this informative.


Now that you know that in general it is possible to safely take your medications with medical marijuana, would you like my help? Head on over to the GET HELP page.  I’ll step-by-step walk you through how to safely use medical marijuana with your current prescription and over-the-counter medications.




Research Referenced:

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