What Drugs Should Not be Taken With CBD (Interactions, Side Effects)

CBD (cannabidiol), on its own, is a safe dietary supplement. 

But using CBD along with prescription drugs? 

Not so much. 

Studies show CBD may interact with prescription drugs (Xanax, Ibuprofen, etc.) and cause unwanted side effects. 

Keep reading to learn what drugs should NOT be taken with CBD. We’ll also share three valuable tips for a safe CBD journey.

Jump To:

• What Drugs Should Not be Taken With CBD?
• How Does CBD Interact with Other Drugs? 
  • CBD & Ibuprofen
  • CBD & Adderall
  • CBD & Antibiotics
  • CBD & Thyroid Medication
  • CBD & Metformin
  • CBD & Sedatives
  • CBD & Valproic Acid
  • CBD & Warfarin
• Common Interactions Between CBD and Prescription Medication
• Potential Side-effects of Taking CBD with Other Drugs and Substances
• 3 Helpful Tips For a Safe and Effective CBD Journey

What Drugs Should NOT be Taken With CBD? 

The research on CBD drug interaction is limited and still in the early stages.

But several clinical trials suggest CBD and prescription drugs have a common link. 

(More on that later.)

The result?

CBD or medical cannabis products (that contain CBD) may cause adverse or unintended effects when taken with certain prescription medicines.

Here’s a list of drug groups and medications that may interact with CBD. 

Avoid CBD if you’re on these medications:

How Does CBD Interact with Other Drugs?

While scientific research on the subject is limited, most clinical trials suggest CBD and certain prescription drugs may interact in the body.

According to these trials, here’s how CBD and drug metabolism may work:

CBD and most prescription medicines (almost 60% of marketed meds) are metabolised by the same liver enzyme system — Cytochrome P450 (aka CYP450). 

This Cytochrome P450 enzyme class comprises 50 different enzymes. 

Of these, only six are responsible for 90% of the drug metabolism, including the CYP2D6 and CYP3A4 enzyme.

So how does the CYP450 system process CBD?

The CYP450 enzyme breaks down the cannabinoid content in the CBD product into molecules that the body can easily absorb.

But in the process, CBD can affect the CYP450 system and disrupt the way it functions.

How does CBD disrupt the Cytochrome P450 system?

CBD competes with the compounds of prescription drugs, preventing the CYP enzymes from breaking down the drugs effectively. 

This inhibition alters the concentration of prescription drugs in your blood’s serum levels.

According to a study by Harvard Medical School, this altered concentration of drugs may:

• Reduce or nullify the effects of the medicine
• Raise the risk of side effects

Want an example?

A JCI Insight study concludes CBD may help reduce blood pressure. 

So taking it with hypertension medicines (like calcium channel blockers) may reduce blood pressure to dangerously low levels.

Now:

The CYP system inhibition by CBD use is influenced by:

•  CBD dosage
•  A person’s physiology
•  Type of CBD (full spectrum CBD, broad-spectrum CBD, and CBD isolate). 

The good news?
If the cannabidiol dosage is low enough, it might not have a noticeable effect on the CYP450 enzyme.

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Common Interactions Between CBD and Prescription Medication

Here’s how CBD interacts with some common medications:

A. CBD and Ibuprofen

Ibuprofen is a common drug used for chronic pain and inflammation. 

Here’s the deal:

There is NO reported CBD interaction with Ibuprofen yet.

But there could be potential CBD drug interactions and unwanted side effects when taking the two together.

According to a Journal of Neurology Research study, taking Ibuprofen with high doses of CBD can lead to nervous system damage and further complications. 

B. CBD and Adderall

Studies show frequent use of CBD products (like CBD oil and creams) can make ADHD medication, like Adderall, less effective. 

Moreover, CBD interaction with ADHD medication may cause unwanted side effects like decreased appetite.

C. CBD and Antibiotics

According to the World Health Organization, antibiotics prevent and treat bacterial infections.

There could be CBD drug interactions when taking CBD with antibiotics like Erythromycin.

What’s the real story here?

Preliminary clinical trials show CBD may increase the risk of side effects common with antibiotic use, such as drowsiness and nausea. 

D. CBD and Thyroid Medication

There’s NO conclusive research on the potential drug interaction between CBD products and thyroid medication. 

But some patients report mild nausea when taking thyroid medication alongside CBD. 

What’s more?

Studies show CBD may help treat hypothyroidism. 

But taking a CBD product with a hypothyroid drug like Levothyroxine may enhance the drug’s effects — leading lead to a health condition called hyperthyroidism.

E. CBD and Metformin

Metformin is a prescription drug used to manage type 2 diabetes. 

According to a study by the American Diabetes Association, CBD has minimal impact on glucose levels and has a low risk of interacting with Metformin.

F. CBD and Sedatives 

Sedative drugs, such as Xanax, have no significant adverse effects when taken with CBD.

But that does NOT rule out the risk of potential drug interaction — CBD may enhance the sedative effect induced by these drugs. 

The result?

Patients may feel extreme drowsiness or sleepiness.

G. CBD and Valproic Acid

Valproic acid is a prescription drug for treating epilepsy and bipolar disorder. It’s also occasionally used to treat severe migraines.

What could happen if you take CBD with valproic acid?

Valproic acid is a powerful drug with a high possibility of drug interaction, especially with high doses of CBD. 

Studies show the interaction may affect your liver enzyme composition and impair liver function. 

H. CBD and Warfarin

Warfarin, a common blood-thinning prescription drug, is used to treat blood clots.

Now:
Both CBD and warfarin are metabolised by the CYP system (CYP3a4 enzyme).

So CBD could compete with warfarin, preventing the CYP system from breaking down the drug. 

The problem?

If warfarin stays too long in the body, it can lead to unwanted side effects such as excessive bleeding.

Potential Side Effects of Taking CBD With Other Drugs 

According to the World Health Organization, CBD is safe and well-tolerated in humans in regular doses. 

But as we mentioned earlier, taking a CBD or cannabis based product (that contains CBD) with other meds could lead to an adverse effect in a patient. 

It may amplify the side effects of prescription medication and lead to another health condition.  Yikes!

Here are some potential side effects of CBD drug interaction:

• Increased lethargy and fatigue
• Irregular or reduced appetite 
• Chances of diarrhoea and nausea 
• Dizziness
• Increased blood pressure
• Cardiac risk

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3 Helpful Tips For a Safe and Effective CBD Journey

Feeling nervous about using CBD alongside your prescription meds? 

Don’t worry. 

Here are some tips to ensure a safe and beneficial CBD experience:

1. Consult a Healthcare Provider

Planning to add CBD to your daily healthcare routine?

After all, this wellness supplement has shown the potential to ease symptoms of depression, anxiety, and thyroid conditions.

The therapeutic compound may also help combat high cholesterol and manage symptoms of diabetes, epilepsy, and other severe medical conditions.

But remember: CBD could interact with prescription medicines. 

If you’re already on other prescription medication, we suggest you practice caution.

Consult your doctor before starting a CBD routine to minimise the risk of CBD drug interactions. 

A healthcare provider could assess potential interactions with the CYP450 system and provide medical advice.

2. Monitor Dosage When Taking CBD With Other Drugs.

As we said earlier, a low dosage of cannabidiol may not have a noticeable effect on CYP activity.

How?

A low dosage ensures the cytochrome P450 enzyme system can break down prescription meds sufficiently. This will regulate the drug’s blood serum levels, reducing potential drug interaction risk. 

Bottom line:  Monitor your CBD dosage when taking it with other prescription drugs or over-the-counter medications.

Avoid taking high doses to enjoy the beneficial effects of CBD and negate drug interactions.

3. Use High-Quality and THC-Free CBD Products

CBD is the therapeutic compound found in the hemp and cannabis plant.  

However, these plants also contain THC or tetrahydrocannabinol.

What’s THC?

THC is a highly psychoactive and addictive compound that can overwhelm your body’s endocannabinoid system (ECS). The ECS regulates bodily functions like mood, appetite, inflammation, etc. 

Now:

Any CBD product with THC is illegal in the UK and many parts of the world. 

What’s worse?

THC may adversely interact with prescription meds, increasing the overall risk.

So whether you’re buying a CBD edible or topical CBD oil, CBD cream, or any other product, ensure it’s 100% THC-free.

We know what you’re thinking… How to ensure a CBD product is THC-free?

Follow these tips when you go CBD shopping:

• Check the Certificate of Analysis (CoA) of the topical CBD oil, CBD gummy, or CBD cream. It helps you verify if the product contains harmful additives like THC, pesticides, or heavy metals.  
• Buy from reputed brands, like Love Hemp, Provacan, and Vitality CBD, that sell THC-free CBD products. 

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CBD may interact with some prescription medicines, but you can minimise the risk by following our helpful tips. 

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