What drugs should NOT be taken with CBD

What drugs should NOT be taken with CBD

CBD is a popular natural supplement, but it's important to know that it can interact with certain medications.

There are some  drugs, which should not be taken with CBD. The most common ones include antidepressants, blood pressure medications and anti-seizure medications. It is always advisable to talk to a doctor about the risks and side effects before taking any new medication - this is especially important when taking CBD too.

Here is a quick overview of what drugs should not be taken with CBD. These medications are most commonly known to have some sort of interaction when taken together with CBD:

Drug Group

Common Drugs

Angiotensin II Blockers

Azilsartan, Eprosartan

Antiarrhythmics & anticoagulants

Flecainide, Warfarin


Azithromycin, Ofloxacin



Anticonvulsants/ Antiepileptic Medication

Lamictal, Dilantin, Valproic Acid






Propofol, Fentanyl




Xanax, Clobazam

Calcium Channel Blockers

Amlodipine, Cardizem

HIV Antivirals


HMG CoA Reductase Inhibitors (Statins)

Atorvastatin, Pitavastatin

Immune Modulators

Thalidomide, Lenalidomide

Non-Steroidal Anti-Inflammatory Drugs (NSAID) Drugs

Ibuprofen, Opioid

Oral Hypoglycemic Agents

Metformin, Glipizide

Proton-Pump Inhibitors

Omeprazole, Rabeprazole



Steroids and Corticosteroids

Betamethasone, Dexamethasone

CBD can increase the side effects of medications

Although CBD is generally considered safe, it can cause some side effects. These include:

  • drowsiness
  • dizziness
  • nausea
  • diarrhoea
  • dry mouth
  • liver damage (in extremely rare cases).

Taking CBD with other medications that have similar side effects may increase the risk of unwanted symptoms or potential poisoning. Taking CBD at the same time as over-the-counter and prescription drugs that cause drowsiness, such as opioids, antipsychotics, antidepressants and antihistamines, can lead to increased drowsiness, fatigue and possibly accidental falls.

How does CBD interact with drugs?

Many medicines are broken down by enzymes in the liver.

CBD inhibits the enzyme cytochrome P450, which is responsible for the breakdown of many prescription drugs in the liver. Consequently, taking CBD at the same time as medications that are metabolised by this enzyme can lead to increased drug levels in the blood and increase the risk of side effects.

Researchers at Penn State College of Medicine evaluated the available information on five prescription drugs that contain cannabinoids: Anti-nausea drugs used during cancer treatment (Marinol, Syndros, Cesamet); a drug used primarily for muscle spasms in multiple sclerosis (Sativex); and a drug for seizure disorders (Epidiolex).

The researchers drew up a list of 57 drugs for which a change in concentration can be dangerous. The list includes a variety of drugs, from heart medications to antibiotics, that can be affected by CBD or THC.

Do all forms of CBD interact with drugs?

No. The faster and more efficiently CBD is absorbed into the bloodstream, the more likely it is to interact with medications.

For example, CBD enters the bloodstream most quickly through vaping or smoking and reaches a high concentration within 30 minutes, increasing the risk of acute side effects.

CBD oil taken sublingually is absorbed moderately quickly, but not as quickly as vaping, which reduces the risk of interactions. 

In the case of foods fortified with CBD, the CBD takes significantly longer to be absorbed and it is less likely that a high concentration will be reached. Nevertheless, even here the concentration may eventually be high enough to cause problems or interact with other drugs.

CBD for topical use, such as creams and lotions, does not usually enter the blood in sufficient quantities to interact with other medications.

What is the "grapefruit test"?

Some people use the so-called "grapefruit test" as a guide to avoid CBD if their medication has a grapefruit warning on the label.


More than 85 medicines have interactions with grapefruit and other citrus fruits such as oranges, grapefruit and tangelos. This is because chemicals in grapefruit known as furanocoumarins inhibit CYP3A4 in a similar way to CBD. The result is slower metabolism of drugs.

Grapefruit warnings are common with various drugs, such as:

  • Antibiotics and antimicrobials
  • Cancer drugs
  • Antihistamines
  • Antiepileptic drugs
  • Blood pressure medicines
  • Blood thinners
  • Cholesterol medicines
  • Corticosteroids
  • Immunosuppressants
  • Pain medications
  • Prostate medications

While this is not an official way to find out if your medications interact with CBD, it can provide a first clue into what drugs should not be taken with CBD.

What drugs should not be taken with CBD - insights from real users

At Nordic Oil, we care deeply about the well-being of our customers. As a CBD company, we cannot and are not allowed to provide medical information, so we would like to share with you feedback from our customers who have taken CBD with medications and have shared undesirable interactions with us.

Of course, these adverse effects may have other causes and are not necessarily related to the use of cannabidiol with drugs, but a possible association should not be ignored.

The following list is based solely on feedback from customers and, where known, includes the exact drug and/or supergroup of the drug:

Medication taken Observed interactions
Beta blockers Arythmia
Antihypertensives, beta blockers, stomach tablets Palpitations, diarrhoea, constipation
Blood thinners, anti-hypertensives Diarrhoea
Bromazepam (benzodiazepine) Palpitations, uneasiness
Cholesterol-lowering drugs, blood pressure-lowering drugs Severe dizziness, drowsiness
Diazepam (benzodiazepine), Novalgin Drowsiness
Diclofenac (non-steroidal anti-inflammatory drugs) Diarrhoea
Duloxetine (SSNRI), aripiprazole (atypical neuroleptic) Palpitations and nausea
Letrazole (aromatase inhibitor) Cravings, insomnia
Methylphenidate, antidepressant Stomach pain

Note: Please do not consider this list to be exhaustive or reliable, it is only intended to provide an indication of which medicines may interact with CBD. We always advise you to consult a doctor before taking CBD if you are on any medication.

Because everyone reacts differently to substances (and to combinations of different substances), it does not necessarily mean that you will experience the same interactions as a person taking the same medication as you. It also doesn't mean that just because a person on the same combination of medication and CBD tolerates it well, you won't experience any interactions.

Some of our customers have also told us that spacing out the intake can be helpful in reducing the risk of interactions. However, this statement should be taken with a grain of salt as medications naturally break down at different rates and this varies from person to person.

How to take CBD safely while using medication at the same time

Talk to your doctor about it first if you want to try CBD as an add-on therapy to relieve the symptoms of a particular condition.

He or she can help you find the right CBD product and dosage and make sure you can take it safely with your drugs. In certain situations, your doctor may monitor the blood plasma levels of certain medications you are taking.

More data and research is needed to conclusively assess interactions with other medications. Toxic overdose of CBD alone is not known to occur, but patients with liver damage should keep a close eye on their liver function. Your doctor can help you find the right CBD product and dose, and make sure you can take it with your medications. In certain situations, your doctor may want to monitor your blood plasma levels of certain medications you are taking.

If you have any questions about the use and dosage of cannabidiol, as well as possible side effects of CBD, we are happy to help - but please understand that we cannot provide information about interactions with your drugs, nor can we comment on any contraindications to taking CBD. In both cases, your doctor should be your first point of contact.

Under no circumstances should you stop taking your medication to try CBD - be sure to check with your doctor before doing so.

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.