What drugs should not be taken with CBD?

Is CBD safe to take with other medications? The short answer is sometimes but it really depends on the medication!

This weekend after a long conversation with a customer who was calling about CBD oil for his dad, we were both excited about how CBD oil might be able to help his dad with an upcoming flight he had to take. 

But just before I ended the call, I asked the most important question - is your dad on medication currently?

Yes he was and yes there were potential interactions with the medication. We both left the call deflated. This is an important question and one which should have been asked upfront. 

If you are currently taking medication, it’s important you are aware CBD does interact with a small number of medications.

The advice from the UK Food Standards Agency (FSA) position is

If you are currently taking any medication, you should consult your pharmacist or doctor before taking CBD. 

can i take CBD with my medication


How does CBD interact with other medications ?

We are in the early years of fully understanding CBD and having a full published exhaustive list of all the medications that CBD interacts with.

However, we do know that CBD works by inhibiting the P450 cytochrome isozyme in the liver.  This means that any other medications that are metabolised by the P450 cytochrome will also be affected.

It is thought that when CBD is taken alongside other medications that are metabolised by the P450 enzyme, medications taken alongside CBD will not be broken down enough causing higher than normal levels of these medications in the blood - i.e. their effects will be stronger and they may cause a toxic build up.

grapefruit cut in half

How can you tell if CBD interacts with medication?

A very quick way of understanding if CBD can interact with a medication is to look for the ‘avoid grapefruit' warning on the back of the medication.

That is, grapefruit interacts in the same way as CBD does by inhibiting the CYP3A4 enzyme leading to increased or decreased amounts of certain drugs.

What medications does CBD oil interact with?

Published studies which show interactions with CBD are generally at high doses. At very low doses, for example below 50mg, it is thought that the chance of a clinically significant drug interaction is probably quite low.

However, the following medications are thought to interact:

  • Anti-epileptics
  • Anti-coagulants
  • Antibiotics
  • Anti-depressants
  • Immunosuppressive agents
  • Cancer immunotherapy drugs

CBD drug interactions list 

The following is a non-exhaustive list of medications that contain a ‘grapefruit warning’ and should be avoided:

  • Daliskiren (Tekturna)
  • Alprazolam (Xanax)
  • Amiodarone (Pacerone)
  • Atorvastatin (Lipotor)
  • Carbamazepine (Biaxin)
  • Cilostazol (Pletal)
  • Clarithromycin (Biaxin)
  • Cyclosporine (Gengraf)
  • Colchicine
  • Dronedarone
  • Erythromycin (Eryped)
  • Felodipine (Plendil)
  • Fentanyl
  • Fexofenadine (Allegra)
  • Flibanserin (Addyi)
  • Indinavir (Crixivan)
  • Ioratadine (Claritin)
  • Iosartan (Cozaar)
  • Iovastatin
  • Nilotinib (Tasigna)
  • Naloxegol (Movantik)
  • Palbociclib (Ibrance)
  • Pazopanib (Votrient)
  • Pimozide (Orap)
  • Ranolazine (Ranexa)
  • Saquinavir (Invirase)
  • Sildenafil (Viagra)
  • Simvastatin (Zocor)
  • Tadalafil (Adcirca)
  • Vardenafil (Levitra, Staxyn)
  • Verapamil (Calan)
  • Warfarin

Source: The CBD Book