Before I get to the list of drugs there is a need to at least briefly talk about how CBD interacts with other drugs, and to give you a little information to clarify what the list is all about.
While Cannabidiol (CBD) is for the most part quite safe, with reasonably mild side effects, when taken with other drugs there is the possibility of interactions that may be of concern.
You may want to review our article What is Cannabidiol (CBD)?. It contains relevant information.
If you ask, ‘Can CBD interact with Drugs?’, the answer is certainly ‘Yes’. However, to date, there have not been many studies on CBD drug interactions. For most drugs, little is known about specifics, such as at what dosage levels CBD interacts with a drug, or even if the interactions are a significant health risk.
The only real study of interactions came from studies for the drug Epidiolex, which is used to treat a few uncommon forms of epilepsy. Those studies found that high doses of CBD can interact and produced high blood levels of other antiepileptics drugs[1]. These include drugs such as clobazam, eslicarbazepine, rufinamide, topiramate, valproate, and zonisamide. This interaction can result in more aggressive seizures.
How does CBD Interact with Other Drugs?
Interactions primarily happen because Tetrahydrocannabinol (THC) and Cannabidiol (CBD) are both substrates and inhibitors of cytochrome P450 enzymatic pathways.[2] Due to this strong interaction with the enzyme system in the liver,[3] CBD prevents other medications from accessing the enzymes and this can lead to a build-up of those medications in the system.
Our article What is Tetrahydrocannabinol (THC) is well worth reviewing.
A study by Lester Bornheim in 1992 found that even a low dosage of CBD can inhibit the enzymes and contribute to prolonged concentrations of clobazam and norclobazam.
A complication is that this enzyme system in the liver is responsible for processing about 60% of all pharmaceuticals.[4]
Types of drugs that are processed by these enzymes include –
- Anesthetics
- Angiotension II blockers
- Anti-arrythmics
- Antibiotics
- Anticoagulants and antiplatelets
- Antiepileptics
- Antidepressants
- Antihistamines
- Antipsychotics
- Benzodiazepines
- Beta blockers
- Calcium channel blockers
- Chemotherapy drugs
- Estrogen Modulators
- HIV antivirals
- HMG-CoA reductase inhibitors
- Immune modulators
- Nonsteroidal anti-inflammatory drugs
- Oral hypoglycemic agents
- Proton-pump inhibitors
- Prokinetics
- Sedatives
- Steroids
- Sulfonylureas
The Grapefruit Connection with CBD
Interestingly, grapefruit juice interacts with the enzymes in the liver in the same way as CBD, and many medications actively warn that they should not be taken in conjunction with grapefruit juice.
We have included in our list below such medications for this very reason.
It seems that a good rule of thumb is that if you are taking medications that have a warning about grapefruit juice then you should absolutely talk to your medical professionals about taking CBD.
Summary
Because there is a lack of knowledge about CBD dosage regards interactions and even the actual concentration of CBD in available products, care is essential when taking CBD in conjunction with other drugs.
There is a real risk that patients, especially those that are taking high doses of CBD, may inadvertently overdose on other medications due to the build-up in their system. These higher doses can cause a whole range of issues. For example, chemotherapy drugs require very specific doses to be effective. Too high a dose may cause toxicity and too low a dose can be ineffective.
In summary, mixing CBD with other drugs is not a well-documented subject. We need a great deal more research and studies to understand all the side effects.
It is certain that CBD does affect the cytochrome P450 enzymatic pathways and thus can result in higher levels of drug in the system. This can then lead to overdoses and ineffectiveness of prescribed medications. But we don’t really know all the drugs or even the dosage of CBD involved.
In short, before taking CBD, it is essential that you discuss taking CBD with your medical professionals to reduce the risk of any drug interactions.
A List of Drugs that May Interact with CBD
It is important to note that the drug groups mentioned above include far more drugs than we have listed below. We have listed only drugs, and the brand names, that were specifically mentioned throughout our research.
The list includes drugs that have some reported drug interaction, but please note that the product used may have include some level of THC. It is possible the interaction may have been due to the presence of THC.
Some of these were also included because they are drugs that have warnings about drinking grapefruit juice while using the drug. As mentioned, grapefruit juice interacts with the enzymes in the liver in a very similar way to CBD, and the interaction with grapefruit juice for these drugs can have dangerous side effects.
Mostly, a drug is included because CBD interaction will potentially result in an increase in the drug in the system due to the liver not being able to break it down. Where possible we have added other relevant notes.
Please note that some of these drugs are known by other names and this list is certainly not complete.
We have highlighted in red the drugs that were mentioned as having major interactions.[5]
Please don’t assume that these drugs can’t be taken with CBD, or that your drug is safe if it isn’t listed here. You must consult with your medical professionals regards your drugs and using CBD.
| Drug | Notes |
| Abstral ® | See Fentanyl. |
| Accurbron ® | See Theophylline. |
| Actiq ® | See Fentanyl. |
| Adalat ® | See Nifedipine. |
| Addaprin ® | See Ibuprofen. |
| Advil ® | See Ibuprofen. |
| Aerolate ® | See Theophylline. |
| Afeditab ® | See Nifedipine. |
| Alcohol | Additive CNS depressant effects |
| Allegra ® | See Fexofenadine. |
| Alprax ® | See Alprazolam. |
| Alprazolam | Interacts with grapefruit juice. Can have dangerous side effects. |
| Altocor ® | See Lovastatin. |
| Altoprev ® | See Lovastatin. |
| Amiodarone | Interacts with grapefruit juice. Can have dangerous side effects. |
| Amitid ® | See Amitriptyline. |
| Amitril ® | See Amitriptyline. |
| Amitriptyline | |
| Amlodipine | |
| Amvaz ® | See Amlodipine. |
| Antabuse ® | See Disulfiram. |
| Aption ® | See Eslicarbazepine. |
| Aquaphyllin ® | See Theophylline. |
| Arymo ® ER | See Morphine. |
| Asbron ® | See Theophylline. |
| Ativan ® | See Lorazepam. |
| Atorvastatin | Interacts with grapefruit juice. Can have dangerous side effects. |
| Avinza ® | See Morphine. |
| Banzel ® | See Rufinamide. |
| Biaxin ® | See Clarithromycin. |
| Brisdelle ® | See Paroxetine. |
| Bronkodyl ® | See Theophylline. |
| Caffeine | High doses may counter the stimulant effect and result in a sedative effect. |
| Calan ® | See Verapamil. |
| Cambia ® | See Diclofenac. |
| Carbamazepine | Interacts with grapefruit juice. Can have dangerous side effects. |
| Carbatrol ® | See Carbamazepine. |
| Carisoprodol | |
| Cataflam ® | See Diclofenac. |
| Cedaprin ® | See Ibuprofen. |
| Celebrex ® | See Celecoxib. |
| Celecoxib | |
| Chlormethiazole | |
| Chlorpromazine | Increase in clearance of chlorpromazine, but in the study, users were smoking cannabis. |
| Chlorzoxazone | |
| Cilostazol | Interacts with grapefruit juice. Can have dangerous side effects. |
| Clarithromycin | |
| Clobazam | Decreases liver function and increases the concentration of Clobazam, thus its side effects. |
| Clonazepam | |
| Clozapine | |
| Clozaril ® | See Clozapine. |
| Codeine | We have not included the brand names for Codeine. Follow the link to discover more. |
| Colchicine | Interacts with grapefruit juice. Can have dangerous side effects. |
| Colcrys ® | See Colchicine. |
| Conzip ® | See Tramadol. |
| Cordarone ® | See Amiodarone. |
| Coumadin ® | See Warfarin. |
| Coumarin | |
| Covera ® | See Verapamil. |
| Cozaar ® | See Losartan. |
| Crixivan ® | See Indinavir. |
| Cyclosporine | |
| Decadron ® | See Dexamethasone. |
| Depakene ® | See Valproic Acid. |
| Depakote ® | See Valproic Acid. |
| Desipramine | |
| Dexamethasone | |
| Dexpak ® | See Dexamethasone. |
| Diazepam | |
| Diclofenac | |
| Dilantin ® | See Phenytoin. |
| Disipal ® | See Orphenadrine. |
| Disulfiram | |
| Dronedarone | Interacts with grapefruit juice. Can have dangerous side effects. |
| Duraphyl ® | See Theophylline. |
| EES ® | See Erythromycin. |
| Effexor ® | See Venlafaxine. |
| Elavil ® | See Amitriptyline. |
| Elixicon ® | See Theophylline. |
| Elixomin ® | See Theophylline. |
| Elixophyllin ® | See Theophylline. |
| Eloxatin ® | See Oxaliplatin. |
| Endep ® | See Amitriptyline. |
| Epitol ® | See Carbamazepine. |
| Equetro ® | See Carbamazepine. |
| Erlotinib | |
| ERY-C ® | See Erythromycin. |
| Ery-Tab ® | See Erythromycin. |
| Erythrocim ® | See Erythromycin. |
| Erythromycin | Interacts with grapefruit juice. |
| Eslicarbazepine | |
| Eulexin ® | See Flutamide. |
| FazaClo ® | See Clozapine. |
| Feldene ® | See Piroxicam. |
| Felodipine | Interacts with grapefruit juice. Can have dangerous side effects. |
| Fentora ® | See Fentanyl. |
| Fexofenadine | Interacts with grapefruit juice. |
| Fentanyl | Interacts with grapefruit juice. |
| Flecainide | |
| Fluotha ® | See Halothane. |
| Flutamide | |
| Gengraf ® | See Cyclosporine. |
| Glipizide | |
| Gloperba ® | See Colchicine. |
| Glucotrol ® | See Glipizide. |
| Halcion ® | See Triazolam. |
| Haldol ® | See Haloperidol. |
| Haloperidol | |
| Halothane | |
| Heminevrin ® | See Clomethiazole. |
| I-Prin ® | See Ibuprofen. |
| Ibuprofen | Increased blood thinning. |
| Imipramine | |
| Inderal ® | See Propranolol. |
| Indinavir | Interacts with grapefruit juice. |
| InnoPran ® | See Propranolol. |
| Isoptin ® | See Verapamil. |
| Itraconazole | |
| Jantoven ® | See Warfarin. |
| Kadian ® | See Morphine. |
| Kalma ® | See Alprazolam. |
| Ketoconazole | |
| Klonapin ® | See Clonazepam. |
| Labid ® | See Theophylline. |
| Lansoprazole | |
| Lipitor ® | See Atorvastatin. |
| Lanophyllin ® | See Theophylline. |
| Lopressor ® | See Metoprolol. |
| Lorazepam | |
| Losartan | Interacts with grapefruit juice. |
| Lovastatin | |
| Meloxicam | |
| Methoxyflurane | |
| Metoprolol | |
| Mevacor ® | See Lovastatin. |
| Midol ® | See Ibuprofen. |
| Mobic ® | See Meloxicam. |
| Morphabond ® | See Morphine. |
| Morphine | |
| Motrin ® | See Ibuprofen. |
| MS Contin ® | See Morphine. |
| Multaq ® | See Dronedarone |
| Nelfinavir | |
| NeoProfen ® | See Ibuprofen. |
| Neoral ® | See Cyclosporine. |
| Nifedical ® | See Nifedipine. |
| Nifedipine | |
| Nifeditab ® | See Nifedipine. |
| Niravam ® | See Alprazolam. |
| Nizoral ® | See Ketoconazole. |
| Nolvadex ® | See Tamoxifen. |
| Norflex ® | See Orphenadrine. |
| Norpramin ® | See Desipramine. |
| Norvasc ® | See Amlodipine. |
| Omeprazole | |
| Omesec ® | See Omeprazole. |
| Ondansetron | |
| Onfi ® | See Clobazam. |
| Onmel ® | See Itraconazole. |
| Onsolis ® | See Fentanyl. |
| Oramorph ® SR | See Morphine. |
| Orphenadrine | |
| Oxaliplatin | |
| Pacerone ® | See Amiodarone. |
| Paraflex ® | See Chlorzoxazone. |
| Parafon Forte ® | See Chlorzoxazone. |
| Paroxetine | |
| Paxil ® | See Paroxetine. |
| PCE ® | See Erythromycin. |
| Pediamycin ® | See Erythromycin. |
| Pentobarbital | |
| Pexeva ® | See Paroxetine. |
| Phenobarbital | |
| Penthrox ® | See Methoxyflurane. |
| Piroxicam | |
| Phenytek ® | See Phenytoin. |
| Phenytoin | |
| Plendil ® | See Felodipine. |
| Pletal ® | See Cilostazol. |
| Prevacid ® | See Lansoprazole. |
| Prilosec ® | See Omeprazole. |
| Procardia ® | See Nifedipine. |
| Profen IB ® | See Ibuprofen. |
| Progesterone | |
| Promapar ® | See Chlorpromazine. |
| Prometrium ® | See Progesterone. |
| Pronol ® | See Propranolol. |
| Propranolol | |
| Proprinal ® | See Ibuprofen. |
| Qudexy XR ® | See Topiramate. |
| Quibron-T ® | See Theophylline. |
| Ralozam ® | See Alprazolam. |
| Rela ® | See Carisoprodol. |
| Risperdal ® | See Risperidone. |
| Risperidone | |
| Roxanol-T ® | See Morphine. |
| Rufinamide | |
| Rybix ® | See Tramadol. |
| Ryzolt ® | See Tramadol. |
| Sandimmune ® | See Cyclosporine. |
| Secobarbital | |
| Seconal ® | See Secobarbital. |
| Slo-Bid ® | See Theophylline. |
| Slo-Phyllin ® | See Theophylline. |
| Soltamox ® | See Tamoxifen. |
| Soma ® | See Carisoprodol. |
| Somophyllin ® | See Theophylline. |
| Sporanox ® | See Itraconazole. |
| Strifon Forte ® | See Chlorzoxazone./td> |
| Sustaire ® | See Theophylline. |
| Sympazan ® | See Clobazam. |
| Synophylate ® | See Theophylline. |
| T-Phyll ® | See Theophylline. |
| Tambocor ® | See Flecainide. |
| Tamoxifen | |
| Taperpak ® | See Dexamethasone. |
| Tarceva ® | See Erlotinib. |
| Tegretol ® | See Carbamazepine. |
| Testosterone | |
| Theo-24 ® | See Theophylline. |
| Theo-Dur ® | See Theophylline. |
| Theobid ® | See Theophylline. |
| Theochron ® | See Theophylline. |
| Theoclear ® | See Theophylline. |
| Theolair ® | See Theophylline. |
| Theolixir ® | See Theophylline. |
| Theophyl ® | See Theophylline. |
| Theophylline | |
| Theovent ® | See Theophylline. |
| Thorazine ® | See Chlorpromazine. |
| Tofranil ® | See Imipramine. |
| Topamax ® | See Topiramate. |
| Topiramate | |
| Toprol ® | See Metoprolol. |
| Tramadol | |
| Triazolam | |
| Trokendi XR ® | See Topiramate. |
| Ultram ® | See Tramadol. |
| Ultraprin ® | See Ibuprofen. |
| Uni-dur ® | See Theophylline. |
| Uniphyl ® | See Theophylline. |
| Valium ® | See Diazepam. |
| Valproate | See Valproic Acid. |
| Valproic Acid | Can cause liver damage and the CBD can increase the chance of injury. |
| Valrelease ® | See Diazepam. |
| Venlafaxine | |
| Verapamil | |
| Verelan ® | See Verapamil. |
| Versacloz ® | See Clozapine. |
| Viracept ® | See Nelfinavir. |
| Voltaren XR ® | See Diclofenac. |
| Warfarin | Increased blood thinning.[6] |
| Xanax ® | See Alprazolam. |
| Zipsor ® | See Diclofenac. |
| Zofran ® | See Ondansetron. |
| Zonegran ® | See Zonisamide. |
| Zonisamide | |
| Zorvolex ® | See Diclofenac. |
| Zuplenz ® | See Ondansetron. |
