cbd contraindications - happy hemper

CBD contraindications: when and why to watch out for the use of the substance

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Did you know that some drug interactions and health conditions can cause cannabidiol to cause some uncomfortable effects? Today we are going to talk about CBD contraindications.

The World Health Organization (WHO) considers cannabidiol a safe compound with a minimal chance of negative side effects on human health.  

However, this does not mean that it does not act like any other type of substance, with the power to increase, decrease or cause adverse reactions.

So it is very important to know what the effects of some interactions are, especially if you take frequent prescription drugs, such as antidepressants and anticonvulsants.

Find out more about CBD contraindications and how you can take care to get the best experience with the substance. 

CBD and other drugs: how does this interaction work?

When we take medicine, the body carries out metabolisation so that the ingested substances are absorbed and eliminated. 

This happens mainly in the digestive tract and the liver. 

The CYP450 family of enzymes metabolises at least 50% of prescription medicines. Two of these enzymes are the main ones responsible for metabolising cannabidiol: CYP3A4 and CYP2C19. 

On the other hand, the other substances compete with CBD, being altered by the presence of one or the other. Hence the drug interaction.

But, there is something even more important. CBD is not only processed by CYP enzymes. 

After all, it also interacts by inhibiting or stimulating its action, resulting in a decrease in the therapeutic potential of the substances or causing side effects.

But side effects are quite uncommon. 

Thus, studies show that high doses of CBD with certain combinations of substances and health conditions are needed to achieve unwanted effects.

7 contraindications of CBD

1. Interactions with antidepressants

cbd interactions with antidepressants

Like CBD, some antidepressants can increase serotonin receptors. 

Therefore, using more than one drug that has this mechanism can lead to what is called a serotoninergic syndrome. 

  • Symptoms may be: 
  • Muscle spasms
  • Anxiety
  • Restlessness
  • Vomiting
  • Diarrhoea
  • Delirium
  • Rapid heartbeat

2. Interactions with medicines that thin the blood

Warfarin is part of the group of anticoagulants used to prevent thrombosis. 

So people taking this drug in conjunction with large doses of CBD may experience unwanted side effects, such as bleeding.

Studies have shown that the interaction with CBD can cause warfarin to remain in the body for a long time without being broken down. 

After all, the CYP450 enzyme is predominantly responsible for metabolising warfarin, but cannabidiol inhibits this class of enzymes.

3. Heart and arterial problems

To date, almost no clinical research has been done on the interaction of cannabidiol in people with diseases of the cardiovascular system. 

Therefore, it is not indicated to consume CBD when you suffer from severe heart problems. 

Some preliminary studies have shown that it can affect the cardiovascular system, especially if it is taken in high doses. 

In this sense, a drop in blood pressure would occur, giving rise to symptoms such as nausea, dizziness and other cardiac alterations.

4. Allergies to cannabidiol

It is important to note that some people may be allergic to cannabidiol and other compounds in the oil. 

Therefore, at the first signs of skin irritation or anaphylactic reaction, you should stop using it immediately.

5. Interactions with anti-epileptic drugs

Individuals who suffer epileptic seizures may experience adverse drug interactions with CBD. 

  • Valproic acid

Valproic acid is the main medication for treating epilepsy. 

Thus, studies have shown that taking CBD in conjunction with it, can lead to abnormally high levels of liver enzymes, which can lead to liver problems.

  • Phenobarbital and phenytoin

CBD elevates the toxicity of these two anticonvulsants, increasing the drug’s effects on our bodies. 

  • Clobazam and phenytoin

CBD alters their metabolism by increasing the concentration of the substance in the body.

6. Interactions with benzodiazepines

Clobazam, diazepam and lorazepam are just some of the benzodiazepines whose blood levels can be increased with CBD use. 

And, it’s important to be vigilant, as these medications are used by the vast majority of people.

After all, they are prescribed to treat common problems such as insomnia, anxiety and seizures.

Healthcare professionals must keep an eye on patients to avoid serious side effects. 

Some are: 

  • Sleepiness
  • Tiredness
  • Coordination problems 
  • Potential for unintentional falls 
  • Car accidents

7. Herbal supplements and herbs

  • Wormwood (Artemisia absinthium)

This supplement can alter the metabolism of CBD, lowering its blood levels in the body and reducing its effects. 

  • Ginkgo biloba

It alters the metabolism of CBD by inhibiting hepatic enzymes. Therefore, the effect can be significant when high doses of the substance are used.

Happy Hemper Tips

If you still do not fit any of the conditions mentioned and are 100% free to try CBD, check out our products.

  • Topical applications

In the monthly boxes you can receive topical application products, such as CBD creams and lotions, great options to reduce the risks of contraindications.

In addition, you can keep your skin nourished, and hydrated, relieving pain, tension and inflammation. 


  • Cold-pressed CBD oil

Cold-pressed CBD oil is known for its high quality, purity and therapeutic value. 

Check out the text we recently published that may help you better understand the benefits of the cold extraction technique.


Now you know how CBD can interact with some health and drug conditions! 

So, we hope you had a good time reading a little more about the use of cannabidiol.

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