Which drugs should not be taken with CBD gummies?

CBD gummies are generally considered to be safe for healthy adults. However, we always caution our customers to speak to their doctor first if they’re taking medications. That’s because CBD can alter how certain drugs work in the body (known as a “drug interaction”). 

The CBD industry is still fairly young, so while we have a reasonably good idea about how it works in the body and how CBD gummies might interact with other drugs, there’s also a lot that’s yet to be discovered. In this article, we’ll talk about what we’ve learned so far and what it means for you if you take medications. 

CBD and drug interactions

 

Any foreign substance that you ingest has to be metabolised, or broken down. For a huge number of prescription medications, that happens mostly in your liver, thanks to a large family of enzymes called cytochrome P450, or CYP450.

CBD is broken down by this same enzyme family, and it can also influence how some of those enzymes work. 

In some cases, CBD induces, or speeds up, the activity of a CYP450 enzyme. This can cause it to break down drugs faster than it usually would. In other cases, CBD can inhibit a CYP450 enzyme, which means that the enzyme breaks down substances more slowly than it usually would.

Your medication dosage and frequency are calculated based on how these enzymes would work in a typical body, without the influence of things like CBD. So you might be taking the prescribed amount at the recommended time, but take it with CBD and you could be amplifying the effects, or reducing them. 

This is where you could run into problems. 

If your body is breaking down your medication too quickly, it’s going to leave your system sooner than it should. This might mean that you’re not getting the full effects of the medication, for as long as you need them. 

Imagine you’re taking an antibiotic. Even though you’ve taken the correct amount, you might not have enough in your system to fight off the infection.

On the other hand, if your body isn’t breaking down the drug quickly enough, you might still have high levels in your system by the time you take your next dose. That could intensify any side effects and potentially put you at risk of harm.

What if you’ve taken the correct amount, but now you’ve got more than you should have in your system? If your medication causes drowsiness, or it lowers your heart rate, or it slows down your breathing, for example, this can easily be quite dangerous. 

 

What are some common CBD-drug interactions? 

 
 

We know that CBD can interact with a blood thinner called warfarin, raising levels by up to 30%. People taking warfarin are already at risk of uncontrolled bleeding and have to manage their dosage very carefully as a result, so this could be one of the more dangerous interactions. 

We also know that CBD can affect:

  • • Antiepileptics, e.g. clobazam, valproate. 
  • • Antibiotics, e.g. erythromycin, clarithromycin. 
  • • Heart medications, e.g. calcium channel blockers. 
  • • Medications that cause drowsiness, e.g. benzodiazepines, antipsychotics. 
  • • Antidepressants, e.g. fluoxetine, duloxetine. 

CBD might also affect how anaesthesia works. If you’ve been taking or considering CBD gummies and you’re due to have surgery, be sure to let your anaesthetist know so that they can plan your anaesthesia properly. 

The grapefruit test 

 

Researchers are still studying how CBD interacts with drugs and there’s a lot of work left to do. In the meantime, you can use “the grapefruit test” as a rule of thumb. 

Lots of medications have what’s known as a “grapefruit warning”, advising against eating grapefruit or drinking grapefruit juice while taking the medication. That’s because grapefruit also has an effect on CYP450, and can influence how certain medications work.

If your medication has a grapefruit warning, then it’s very possible that it would be influenced by CBD as well. If so, definitely speak to your doctor before you consume CBD gummies or other CBD products. 

Speaking to your doctor about CBD


When you understand how CBD affects drug metabolism, it’s easy to see how mixing it with certain drugs could cause some unwanted and potentially harmful effects. This is why we always recommend speaking to your doctor first. 

Your doctor will be able to review your medications and check how they interact with CBD. That doesn’t necessarily mean that you can’t take CBD gummies or other CBD products. In many cases, it might just mean your dosage needs to be adjusted to make sure it’s accurate and safe. Sometimes, your doctor might also want to monitor blood plasma levels of your medications to be sure. 

Whatever you do, it’s important that you don’t try to adjust your dosage on your own, or stop taking medications so that you can take CBD. Always get your doctor’s advice first so you can enjoy CBD gummies safely! 

Speaking of safety…

Your doctor will need to know how much CBD you take. If you’re buying a CBD gummy like ZenBears, you’ll be able to find the exact dosage on the packaging, and that will be verified on the independent lab reports too. However, not all brands will get or publish these lab reports, so you’re essentially taking their word about CBD content. 

There’s also the issue of THC, which has a host of drug interactions of its own. You might know this as the chemical compound that gets you high when you smoke cannabis, and it’s also present in some CBD products in very small amounts. Some brands will advertise a THC-free product, but in reality some have been found to have THC, at illegally high levels in some cases.  

The only way to avoid this is to buy CBD gummies from a brand that publishes independent, third-party lab reports. We recommend doing this anyway, but when you’re mixing CBD with medication, it’s more important than ever to know exactly what you’re getting.