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Medicinal CBD Oil Treatments

CBD Interactions with Common Medications

June 25


common CBD interactions with medications

As the cannabis compound cannabidiol (CBD) has been legal in Australia since 2021, there has been a surge in demand for related products provided individuals are able to present a valid and viable prescription. With this in mind, it’s increasingly important to make yourself aware of the possible CBD interactions with other drugs, and side effects if taken together. This article tackles how CBD interactions occur with a few of the most commonly consumed prescription medications, and explains what happens to your body when taken together.


The Relationship Between CBD and Drug Interactions

CBD, on its own, is often well-tolerated with a few mild side effects (this can, of course, vary from person to person). However, adverse effects may occur when taken in conjunction with a specific medication, as 60% of prescription medications use the same group of enzymes as CBD. 

This may lead to several drug interactions that may inhibit these enzymes, affecting both the metabolism and efficacy of either CBD or the ingested medication.

One of these groups of enzymes is the Cytochrome P450 (CYP), which extensively metabolises CBD. Several drugs – both prescription and over-the-counter medications – may alter the activity of these enzymes as they may contain enzyme inhibitors or inducers.

To provide further context, enzyme inhibitors decrease the rate at which CBD metabolises, leading to higher concentrations of CBD remaining in the bloodstream for longer periods. Enzyme inducers, on the other hand, do the opposite – they speed up the metabolism of CBD, which decreases its potency. 

CBD can also have this effect on medications as well as it can also act as an enzyme inhibitor. Instead of the medication inhibiting CBD’s metabolism, the cannabis compound blocks the medication’s metabolism and intensifies its effects.


Below are the following general drug categories that may have potential interactions with CBD:



Based on available studies, CBD can inhibit the CYP2D6 enzyme. For further context, CYP2D6 is responsible for metabolising and eliminating up to 25% of clinically used drugs.

This affects the therapeutic efficacy and toxicity of certain antidepressants, such as tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs), and leads to increased side effects from their ineffective break-down.

Additionally, the side effects of both CBD and antidepressants may happen simultaneously, causing intensified feelings of drowsiness, sleep disturbances and other disruptive qualia.


Antiepileptic Drugs

While CBD is frequently used in conjunction with anti-epileptic drugs to help prevent some types of seizures, certain medications affect the metabolism of CBD and decrease its efficacy.

Drugs such as oxcarbazepine, carbamazepine, phenytoin, and phenobarbital may lead to adverse effects. For example, CBD increases the anticonvulsant effects of both phenobarbital and phenytoin at the cost of intensifying its toxicity.


Opioid Analgesics

Like antidepressants, CBD also decreases the metabolism of opioids, such as morphine and acetaminophen, by inhibiting enzymes such as CYP2C10 and CYP3A4, and intensifying their side effects. 

CBD slows down the body’s ability to break down these medications, and leads to enhanced pain-relieving effects. However, this also increases the risks of side effects, such as drowsiness, fatigue, lethargy, and intensified toxicity.


Blood Thinners 

CBD may affect the metabolism of blood thinners such as anticoagulants like Warfarin and antiplatelets like Clopidogrel. Since CBD also inhibits the enzyme CYP2C9, it can lead to increased levels of warfarin and a potentially increased risk of bleeding. 

In one review published in 2018, a patient took CBD to manage their epilepsy. This necessitated the need to reduce their warfarin dosage by 30% to decrease any risks of complications.


Blood Pressure Medications

Since CBD has been proven to lower one’s blood pressure, it’s generally a good idea to avoid combining this with blood pressure medications such as ACE inhibitors or Beta Blockers.

This is because CBD may have synergistic effects with these medications and may lead to significantly lower blood pressure levels and increased risks of fainting, dizziness, and lightheadedness.


Key Takeaways – CBD Interactions

While CBD is certainly useful for various health benefits such as reducing inflammation, seizures, and anxiety, potential problems may surface when taking it in conjunction with medications.

With that in mind, we highly recommend using CBD devices under the guidance of your primary healthcare provider. 

They have sufficient knowledge to properly assess and weigh its therapeutic effects against potential CBD interactions with medications, and recommend a more appropriate dose so you can safely experience its benefits without any complications.

For more insights into CBD-related resources, we invite you to subscribe to AltMed’s Podcasts so you can always stay at the forefront of a rapidly changing industry.

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