What drugs should not be taken with CBD? Well, there is a long list of them. And in some cases, these interactions can produce some nasty side effects.
Taking CBD with other drugs can alter the effects of either CBD or other medication — or both.
For this reason, you consult with your doctor about taking CBD or any other drug, particularly if you are already taking medications.
How Drugs Interact with CBD
Over the past years, many people have started using CBD. This trend is not surprising, given CBD’s incredible therapeutic benefits. Also, CBD can relieve various symptoms, such as chronic pain, inflammation, and sleeping disorders such as insomnia, among many others.
Recent studies have found that it is generally safe to use CBD as it has only minor side effects. But there’s one big caveat – it can interact with other medications. The concern has to do with the body’s metabolization of various substances, including CBD.
As you know, the body metabolizes or breaks down the medication or substances you take. The metabolization of drugs happens throughout the body, mainly in the gut and the liver. This is where the interaction between CBD and medications will take place.
CBD Can Inhibit CYP450
Cytochrome P450 is essential in metabolization. This family of enzymes does the work of converting foreign substances for easy elimination from the body. However, some substances or medications can affect these enzymes.
As a result, a person’s drug metabolism may slow down or speed up, altering the body’s drug interaction. Some research has found that CYP450 metabolizes CBD and other cannabinoids.
However, CBD also inhibits CYP3A4 during the process. The CYP3A4 enzyme metabolizes most clinically prescribed drugs. If CBD interferes with this enzyme, then it also affects the breakdown of some of the medications you take. This is why you must be careful when taking CBD at the same time as other medications.
Some Medications Can Also Interfere with CYP3A4
Similarly, other medications can also interfere with CYP3A4. This can result in your body being unable to metabolize CBD effectively. If you take CBD with other medicines, the effects of either CBD or the drug you take may become exaggerated.
The result is that you may experience some unwanted side effects. However, that’s not to say that you can never use CBD while you’re taking medications. You can still use it as an add-on to help ease your symptoms.
But first, discuss your situation with your doctor. They can guide you about the right product, dosage, and schedule for taking CBD that’s safe with the drugs you’re currently taking. This way, you can take advantage of CBD’s therapeutic benefits while continuing medical treatment for your condition.
What Drugs Should Not Be Taken With CBD Oil?
Back to the most critical question, “what drugs should not be taken with CBD?” Studies about the possible interactions between CBD and certain medications are still ongoing. There isn’t much information available yet as research continues to explore drug interactions, but there’s a rule of thumb that should be applied to mixing CBD with other medications.
“Don’t take CBD with drugs that have a grapefruit warning.”
The grapefruit warning indicates that when taking that medicine, you must not consume grapefruit or grapefruit juice. The Food and Drug Administration cautions everyone that consuming grapefruit while taking a specific drug can cause adverse side effects.
Some drugs and grapefruit don’t mix, causing a greater concentration of the medication in a person’s bloodstream. Besides possibly causing severe side effects, it can lead to overdose. It applies not only to grapefruit but other citrus fruits or juices such as Seville oranges.
The reason behind this is a chemical in grapefruit called furanocoumarins. It interferes with CYP3A4 the same way as CBD, slowing the breakdown of certain drugs. Not all medications have this chemical, but there’s a long list of drugs that do.
Here are some types of drugs that usually have the grapefruit warning:
- Antiepileptic drugs
- Blood pressure medications
- Blood thinners
- Erectile dysfunction medications
- GI drugs
- Heart rhythm medications
- Benzodiazepines or sedatives
- Prostate medications
- Pain medications such as NSAIDs
Now let’s take an in-depth look at some of the common medications taken in tandem with CBD.
CBD & Ibuprofen
CBD interacts with CB2 receptors to ease any pain you may be experiencing. Ibuprofen stops the production of prostaglandins by blocking the COX-2. CBD and ibuprofen are both broken down by the same process in the liver.
Because of this, if you use CBD with ibuprofen, it can lead to increased or decreased concentrations in the body.
This means the overall effects of ibuprofen may intensify or reduce, including the accompanying side effects — dizziness, stomach bleeding (ulcers), and high blood pressure.
CBD & Warfarin
Warfarin is an anticoagulation medicine, also known as a “blood thinner.” It’s used to prevent blood clots, encourage the blood’s healthy flow, and decrease certain protein levels in the body. It can cause some alarming side effects, such as headaches and increased bleeding.
It’s a high-maintenance drug that needs constant monitoring. Warfarin poses risks when taken with foods that are high in vitamin K or taken with CBD. Taking Warfarin and CBD concurrently may increase your chances of nosebleeds, bleeding from your gums, dark stools, or unusual bruising.
CBD Oil & Prozac
Prozac or fluoxetine treats several mental health conditions, such as anxiety, depression, OCD, bulimia, and premenstrual dysphoric disorder. It helps ease the symptoms of these conditions but poses a risk of potential side effects.
Currently, there are not many reports of a negative interaction between CBD in conjunction with Prozac. Many patients have even reported an improvement in their depression when combining these two drugs.
CBD and Adderall
Adderall is a medicine used to treat attention deficit disorder (ADD), attention deficit hyperactivity disorder (ADHD), and narcolepsy. Some of its side effects include anxiety, depression, and fatigue, which normally occur when the drug wears off.
CBD has calming effects, which may reduce Adderall’s effects on the body. The two should create a more balanced feeling, especially if the drug’s effects are often too strong. However, CBD used with Adderall may decrease appetite or cause excessive fatigue or relaxation when taken with Adderall.
CBD Oil & Lamictal
Lamictal or lamotrigine is an antiepileptic and anti-convulsive medication. It helps to control and treat epileptic seizures and bipolar disorder. This drug works by restoring the balance of natural substances in the brain.
Some studies report there aren’t any apparent signs that CBD interacts with Lamictal. However, it is difficult to say with complete confidence due to the lack of research. The fact is lamotrigine affects CYP3A4, and as mentioned prior, this can cause problems. As such, it’s essential to consult with your doctor when supplementing Lamictal with CBD.
CBD Oil & Antibiotics
CBD oil is considered safe to use with a low risk of side effects. CBD and antibiotics can both fight infections but in different ways. One study on various cannabinoids found that CBD and THC can affect pathogenic bacteria. However, researchers also don’t know how CBD performs this function.
There is no solid evidence that it’s unsafe to take CBD while on antibiotics. However, the combination of the two has not been studied enough as of yet. It is still safer to avoid taking them together without consulting your doctor first.
CBD Oil & Omeprazole
Omeprazole, also known by the brand name Prilosec, is a proton pump inhibitor (PPI). It’s used to relieve heartburn symptoms, treat gastroesophageal reflux disease (GERD) and other acid-related disorders. To date, there hasn’t been a study conducted that has focused on CBD oil and omeprazole interaction.
However, omeprazole can inhibit the metabolizing enzymes CYP2C19 and CYP2C8. CBD also interferes with various metabolizing enzymes, including CYP2C19. This means there’s a considerable possibility of interaction when you take CBD with omeprazole.
CBD & Thyroid Medications
CBD is also reportedly helpful in managing thyroid conditions. CBD’s anti-inflammatory potential may help ease the pain and inflammation associated with thyroid problems.
One thing that’s known is that both thyroid medications and CBD affect cytochrome P450. They can inhibit these enzymes, possibly causing the accumulation of thyroxine. This can result in hyperthyroidism, as well as side effects that include mild nausea and anxiety.
CBD & Lisinopril
Lisinopril is an example of a blood pressure medication. It’s an antihypertensive medicine under the brand names Lopril and Lisodur, among others. This drug helps lower blood pressure and improves the heart’s pumping power. However, the use of lisinopril can cause dizziness and other side effects.
Blood pressure medications also use the CYP450 pathway when metabolizing. As such, it’s crucial to take CBD cautiously with lisinopril.
Combining the two may cause either one to remain in your system for a longer time, increasing the risk of experiencing side effects. Also, using CBD and lisinopril together may lower your blood pressure too much and make you feel lethargic and weak.
CBD & Prednisone
Prednisone is a glucocorticoid drug used to treat inflammatory conditions. But it is used irregularly due to its potentially severe side effects. Its adverse side effects include dizziness, insomnia, restlessness, sweating, headaches, mood changes, and indigestion.
Prednisone uses the CYP450 enzymes to metabolize. It’s the same family of enzymes that CBD also uses. While there is not enough research to tell whether they interact with each other, the safe course of action is to be cautious in taking both simultaneously.
Summary: CBD is Relatively Safe, But Speak With Your Doctor If Using Other Medications
Most research has found that CBD is safe to use. But since there’s not enough information on combining CBD with other drugs, it’s always better to be careful.
So, what drugs should not be taken with CBD?
For now, it’s best to avoid taking CBD with medications with a grapefruit warning or if using prescription blood thinners, heart medications, diabetes medications, or antibiotics together with CBD unless advised otherwise by your doctor.
- Argueta, D. A., Ventura, C. M., Kiven, S., Sagi, V., & Gupta, K. (2020). A Balanced Approach for Cannabidiol Use in Chronic Pain. Frontiers in pharmacology, 11, 561. 
- Harvard Health Blog. January 11, 2021. CBD and other medications: Proceed with caution. health.harvard.edu 
- Alsherbiny MA, Li CG. (2019). Medicinal Cannabis—Potential Drug Interactions. Medicines. 6(1):3. 
- Giovanni Appendino, Simon Gibbons, Anna Giana, Alberto Pagani, Gianpaolo Grassi, Michael Stavri, Eileen Smith, and M. Mukhlesur Rahman (2008, Aug. 6). Antibacterial Cannabinoids from Cannabis sativa: A Structure−Activity Study. Journal of Natural Products 2008 71 (8), 1427-1430. 
- Lakiotaki, E., Giaginis, C., Tolia, M., Alexandrou, P., Delladetsima, I., Giannopoulou, I., Kyrgias, G., Patsouris, E., & Theocharis, S. (2015). Clinical Significance of Cannabinoid Receptors CB1 and CB2 Expression in Human Malignant and Benign Thyroid Lesions. BioMed research international, 2015, 839403.