In our latest question and answer, the pharmacist discusses the use of CBD with Lamictal and Prilosec. There’s reason to believe that, as safe as CBD has been shown when used alone, it may have the potential to negatively react with other medications to create some unintended side effects. When you take CBD alongside certain medications, it can trigger negative drug interactions. Here we explain what drugs shouldn’t be taken with CBD — and when to consult your doctor if you’re not sure about the potential interactions.
Cannabidiol (CBD) With Prilosec And Lamictal
In our latest question and answer, the pharmacist discusses the use of CBD with Lamictal and Prilosec.
I read your article about possible drug interactions with CBD oil. I’m still confused. I take 50 mg of CBD oil per day in addition to 40mg of Prilosec once a day and 100mg of Lamictal twice per day. It appears to me after reading your article that the Prilosec increases the amount of CBD in my bloodstream but it inhibits the amount of Lamictal in my bloodstream. Is that correct?
At a glance
- Based on the known metabolism of CBD (cannabidiol), Prilosec (omeprazole) and Lamictal (lamotrigine), there are several potential interactions to be concerned with. CBD may increase blood concentrations of both Prilosec and Lamictal due to enzyme inhibition, but more studies are needed to confirm this.
Thank you for reading one of our articles regarding CBD (cannabidiol) interactions. I am more than happy to elaborate on any specific drug interaction you are concerned with.
Based on your question, you are concerned with the use of two drugs with CBD, Prilosec (omeprazole) and Lamictal (lamotrigine), so I will cover both of those for you.
Before discussing those two drugs, it is important to point out that drug interaction studies concerning CBD are lacking. Most potential interactions with CBD are based simply on what we know about its metabolism and the metabolism of other drugs.
Very few studies exist that explore CBD interactions with specific drugs. Currently, the most well-documented interactions are with certain anticonvulsants, like Onfi (clobazam)  , valproate, Topamax (topiramate) and Zonegran (zonisamide)  .
Having said that, let’s take a look at Prilosec and Lamictal.
CBD With Prilosec
Prilosec (omeprazole) is a PPI (proton pump inhibitor) that is used not only to help relieve the symptoms of heartburn but also to treat GERD, ulcers and a variety of excess acid-related disorders. 
Prilosec has been well studied in regard to its metabolism and potential drug interactions. One of the most commonly known interactions clinicians in all areas of practice are aware of is between Prilosec and Plavix (clopidogrel), an antiplatelet medication. 
Prilosec is known to inhibit at least two metabolizing enzymes: 
This is important since metabolizing enzyme inhibition is the most common mechanism behind drug interactions. 
If you take Prilosec in addition to a drug that is metabolized via CYP2C19 or CYP2C8, their blood concentrations could potentially be increased, which could increase the risk of dose-related side effects since they won’t be metabolized as efficiently.
CBD (cannabidiol) is metabolized by a variety of enzymes, most notably CYP3A4 and CYP2C19. 
Theoretically, Prilosec, being an inhibitor of CYP2C19, could potentially increase CBD concentrations. The prescribing information for Epidiolex, a prescription CBD product, discusses this: 
“EPIDIOLEX is metabolized by CYP3A4 and CYP2C19. Therefore, coadministration with a moderate or strong inhibitor of CYP3A4 or CYP2C19 will increase cannabidiol plasma concentrations, which may result in a greater risk of adverse reactions [see Clinical Pharmacology (12.3)]. Consider a reduction in EPIDIOLEX dosage when coadministered with a moderate or strong inhibitor of CYP3A4 or CYP2C19.” Epidioloex Prescribing Information
Interestingly enough, there has been at least one study that reported that Prilosec did not affect CBD concentrations, even though, in theory, we could expect one: 
“. the moderate CYP2C19 inhibitor omeprazole [Prilosec], a proton-pump inhibitor used to treat gastroesophageal reflux disease, did not significantly alter the pharmacokinetics of CBD.” Cannabis Cannabinoid Res. 2016; 1(1): 90–101
Clearly, more studies are needed to see if there truly is an interaction between CBD and Prilosec and whether or not it is clinically significant. Based on the information that is currently available, it doesn’t appear to be overly concerning.
CBD With Lamictal
Clinical studies for cannabidiol show that it can inhibit an enzyme known as UGT2B7 (UDP-Glucuronosyltransferase-2B7).  
Lamictal is predominately metabolized by this enzyme. Therefore, there is the potential that CBD could increase concentrations of Lamictal (due to inhibition of its metabolism), increasing the risk of side effects. 
Like the potential interaction with CYP2C19 substrate drugs, the prescribing information for Epidiolex (the prescription CBD product) states the following regarding UGT2B7:
What Kind of Drug Interactions Can Happen with CBD?
Many consumers are increasingly turning to CBD products as a natural alternative to everything from chronic pain relief to the treatment of ADHD, anxiety, and more. While CBD, one of the many compounds inherent to the cannabis sativa plant, may offer a nice alternative to current treatments, including prescription drugs, it’s important to be smart about how CBD could potentially interact with any other medications you’re taking.
7 Common CBD Oil Drug Interactions
- Antidepressants, such as Fluoxetine or Prozac
- Any drug that causes drowsiness, including antipsychotics and benzodiazepines
- Macrolide antibiotics like Erythromycin and Clarithromycin
- Seizure Medications Like Clobazam, Lamotrigine and Vaproate
CBD has many exciting possibilities when it comes to therapeutic treatment, but it’s important to remember that the research around is in the very early stages. Because researchers haven’t fully explored CBD’s mechanism of action (yet), it can be sometimes be hard to predict whether it will have interactions with other medications, both over-the-counter and prescriptions. What behaves as a safe and natural remedy for one patient could have unintended negative interactions with another patient, depending on the other compounds in the patient’s system.
While we’ll outline some of the most common CBD oil drug interactions, it’s always important to visit with your doctor or consult with a pharmacist if you have any concerns about potential negative side effects.
Does CBD Interact with Medications?
There’s reason to believe that, as safe as CBD has been shown when used alone, it may have the potential to negatively react with other medications to create some unintended side effects.
CBD may at times react with over-the-counter medications, herbal products, and some prescription medications, which underscores the necessity of talking with a doctor or pharmacist before trying CBD products if you’re regularly taking a drug for a heart condition, pain or another medical condition. Some medications should never be taken with CBD, while others can be modified or reduced in order to decrease the chance of a negative CBD drug interaction. And while CBD information for medical professionals is in early phases, your doctor is still the best equipped to provide sound advice about how to safely use CBD for your particular medical condition.
According to Nina M. Bemben, PharmD, BCPS —a specialist in drug interactions—CBD, along with many other medications and compounds, are broken down for the body’s use by the liver enzyme family known as Cytochrome p450. Because CBD acts as an inhibitor to certain CYP enzymes, it could cause other medications in the body to be broken down more slowly—which, unless your doctor lowers your dosage, could lead to increased side effects. On the other hand, CBD can induce other CYP enzymes, which may lead to a faster drug metabolism, resulting in reduced efficacy unless the dosage is increased.
While much research is needed on exactly how CBD behaves within our bodies and how it interacts with various other medications, here’s a good general rule to remember: if you take a drug with a label that features a grapefruit juice warning, it’s a good idea to steer clear of any CBD product while you take that drug. Why? According to the U.S. Food and Drug Administration , a medication with this warning, taken together with grapefruit or grapefruit juice, can manifest at a higher than intended concentration within the blood, potentially causing adverse events.
What does this have to do with CBD? A class of chemicals present in grapefruit juice, known as furanocoumarins, inhibit the enzyme CYP3A4—in much the same way CBD does, resulting in a slower metabolization of medications. So, if you’re taking a medication that features a grapefruit warning, there’s a good chance CBD may cause a few issues with that drug as well. More than 85 different drugs react negatively with grapefruit, including many of the following—you’ll notice a distinct overlap between this list and the list of drugs that commonly have a CBD drug interaction:
- Antibiotics and antimicrobials
- Anticancer medications
- Antiepileptic drugs
- Blood pressure medications
- Blood thinners
- Cholesterol medications
- Erectile dysfunction medications
- GI medications, such as those used to treat nausea and GERD
- Heart rhythm medications
- Mental health medications, such as to treat anxiety, depression, or mood disorders
- Pain management medications
- Prostate medications
The good news? Based on what we know about how CBD is metabolized, there doesn’t seem to be much concern over potential reactions to nonsteroidal anti-inflammatory drugs and/or other prescription medications used to treat the symptoms of arthritis. More good news: there are no reports of any life-threatening interactions that over-the-counter CBD products have had with any herbal, OTC, or prescription drug. Commonly reported side effects have included drowsiness, nausea, diarrhea, dry mouth, a decrease in medication efficacy and changes in appetite or weight.
With the help of your doctor, it’s possible to add CBD to your therapeutic regimen, even if you’re taking another prescription medication that could interact negatively with CBD. It may just be a question of adjusting dosage, monitoring liver function and/or carefully watching for side effects.
We also want to stress that you should never forego your current medication to try CBD without talking with your doctor first. Some medications will need the dosage slowly tapered down in order to safely discontinue use, while others may require careful monitoring.
7 Common CBD Oil Drug Interactions
Let’s take a closer look at common medications CBD oil may negatively interact with:
1. Antidepressants, such as Fluoxetine or Prozac
Some common medications prescribed for depression, such as Fluoxetine and Prozac, when combined with CBD, may increase drowsiness or dizziness. This can be dangerous for patients who are older or who otherwise experience mobility issues, as it may increase the chances for a dangerous or even life-threatening fall.
2. Any drug that causes drowsiness, including antipsychotics and benzodiazepines
Any drug that causes drowsiness, which is a surprisingly large collection, has the potential to combine with CBD for an intensified effect. Anyone who is taking these types of medications combined with CBD is at an increased risk for impaired judgment, falls, and other dangerous situations that result from excessive drowsiness.
3. Warfarin and Clopidogrel
Warfarin is a fairly common drug prescribed as a blood thinner. The most reliable information we have about CBD’s potential interaction with Warfarin comes from studies of the only FDA-approved CBD product, Epidiolex, which is a prescription treatment for rare forms of epilepsy. Epidiolex has been shown to increase blood levels of Warfarin by approximately 30 percent. With this increase comes a higher risk of excessive bleeding. Clopidogrel also interacts with CBD.
4. Macrolide antibiotics like Erythromycin and Clarithromycin
These types of antibiotics are widely prescribed for the treatment of bacterial infections. Because CBD has the ability to slow down or speed up the metabolism of antibiotics by our CPY450 enzymes, taking antibiotics in conjunction with CBD may mean you end up with a higher dose of drugs in your system than is either safe or effective.
Amiodarone is often prescribed to address irregular heart rhythm. CBD metabolism often is slowed down when taken in combination with Amiodarone, resulting in elevated levels of both medications in your system if they’re used together. In addition, both CBD and amiodarone can cause an elevation in liver enzymes, and the effect is exacerbated when the two are taken together.
Levothyroxine is a commonly prescribed thyroid medication. In fact, it is likely the most popular drug prescribed for thyroid issues. When CBD and levothyroxine are taken together, they are forced to compete within the CPY450 enzyme pathways for effective drug metabolism. This kind of drug interaction could cause thyroxine to accumulate, which could result in hyperthyroidism. In addition, when thyroid medications and CBD products are taken too closely together, some patients may experience short-term anxiety and mild nausea.
Seizure medications, like Clobazam, Lamotrigine and Vaproate
Clobazam, Lamotrigine, and Vaproate often are prescribed for patients experiencing seizures, either due to epilepsy or other health conditions. In some cases, CBD has increased the Clobazam levels of children treated with both Clobazam and CBD for epilepsy.
Does CBD Consumption Method Matter?
The manner in which you consume CBD absolutely has an effect on its potential to negatively react with other medications you take. Inhaling CBD, for example, deposits the compound almost immediately into your bloodstream, which allows it to reach peak concentration within 30 minutes. This delivery method avoids the liver’s metabolism, but may still increase the chances that CBD will negatively react with other medications already in your system.
Edible CBD vehicles, like soft chews, CBD gummies, etc., take longer to absorb and reach peak concentration, but they also have the potential to reach a highly concentrated enough level that negative interactions are possible. The same is true for a CBD oil or emulsion tincture .
CBD topicals, such as balms, creams, CBD lotion, etc., are the least likely to react negatively with other medications in your bloodstream because absorption through the skin decreases the amount of CBD that may eventually make its way into your bloodstream.
Other factors that influence both the occurrence and severity of a CBD interaction with other pharmaceutical drugs may include the age of the patient, the dosage amount of both CBD, and the interacting drug, plus any existing underlying medical conditions. Older patients may be at higher risk of potential negative drug interaction for a couple of reasons: first, as we age, the time our bodies take to process compounds like CBD and other medications increases, and second, older patients are more likely to take multiple medications on a regular basis.
Your doctor can help you figure out what type of CBD and dosage may be right for you, considering your medical profile and any medications you already take on a regular basis.
Create a CBD Treatment Plan with Your Medical Team Today!
CBD shows great promise in being able to offer patients relief from a wide variety of medical conditions, but it’s still in the early stages of research. If you want to try CBD, but are already taking a medication to treat your condition, make sure to confer with your doctor before adding CBD to your treatment plan or before using CBD to replace any of your current medications.
Your doctor can help you develop a plan that will let you enjoy the highest therapeutic effect of CBD with the fewest possible side effects. And when you’re ready to purchase high quality, responsible CBD products, our team at Farmer & Chemist is here to help—we have a broad variety of CBD oils, creams, gummies, and more. Our team of pharmacists and pharmacy technicians are also available to answer any questions you may have about the appropriate use of CBD, as well as any potential drug interaction you need to speak to your doctor about.
CBD Drug Interactions – Mixing Cannabidiol and Medications
Are you worried about potential CBD-drug interactions? In this article, we explain the mechanism behind drug metabolism and how CBD may interfere with it.
The range of therapeutic properties offered by CBD (cannabidiol) has spurred its popularity in recent years. This natural compound is known to relieve a host of symptoms, allowing for safer and more effective management of different health conditions.
And unlike THC (tetrahydrocannabinol), CBD is non-intoxicating, so it won’t get you high.
CBD can assist in the treatment of anxiety disorders and depression, inflammation and pain, neurodegeneration, seizure disorders, sleep deprivation, metabolic conditions, neuropathy, migraines, inflammatory bowel disease, and more.
Considering CBD has so many potential health benefits, you may start wondering if it can interact with certain medications used to address the same symptoms — and whether you should or shouldn’t take these drugs with CBD.
Below you’ll find the dos and don’ts of using CBD along with medications.
Let’s start with the don’ts.
What Drugs Should Not Be Taken with CBD
Studies from the Indiana University Department of Medicine have provided a list of pharmaceutical drugs and medications which shouldn’t be taken with CBD.
The list below covers all groups of drugs that can negatively interact with CBD oil.
- Angiotension II Blockers
- Anticonvulsants / Anti-Seizure Medications
- Calcium Channel Blockers
- HIV Antivirals
- HMG CoA Reductase Inhibitors (Statins)
- Immune Modulators
- Non-Steroidal Anti-Inflammatory Drugs
- Oral Hypoglycemic Agents
- Proton-Pump Inhibitors (PPIs)
- Steroids and Corticosteroids
There’s also a group of drugs called “prodrugs” that first need to be processed into their therapeutic compounds instead of being therapeutic compounds on their own. In plain English, the inactive compound is consumed, and once in the body, it turns into the active compound.
If this mechanism is dependant on the CYP450 system (more on that later), a drug interaction can lead to insufficient concentrations of the therapeutic agent in the bloodstream — reducing its potency.
CBD Interaction with Drugs & Medications
This section covers the most common interactions between CBD and medications. If you take any of the substances listed below, make sure to consult your doctor before buying CBD oil.
CBD and Ibuprofen Interaction
Ibuprofen is one of the Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), meaning it can produce similar benefits to CBD in terms of inflammation and pain relief. Previously we’ve mentioned that NSAIDs interact with CBD, which may raise concerns about potential negative interactions between CBD oil and Ibuprofen.
According to a study from the Journal of Neurology Research, there have been no reported interactions between CBD and ibuprofen, although it doesn’t mean they do not exist. Health experts suggest that potential interactions may be dosage-dependent. If a certain dosage threshold is breached, CBD and NSAIDs like Ibuprofen can lead to unforeseen and potentially severe nervous system pathology.
CBD and Adderall Interaction
A 2020 study found that higher doses of medical cannabis led to a decreased use of ADHD medication in adults. Products containing a higher concentration of CBD were linked to lower ADHD scores. This means that CBD can interact with ADHD meds, decreasing their efficacy while providing more pronounced benefits. The potential side effects of interactions between CBD and Adderall may lead to decreased appetite.
CBD and Lamictal Interaction
Using medical cannabis and Lamictal may increase side effects such as dizziness, confusion, drowsiness, and difficulty concentrating. Elderly consumers may also experience impairment in judgment. That being said, none of these side effects were proven to result from CBD use per se. When it comes to interactions between CBD and Lamictal, it can make the medication more or less effective, depending on the dosage.
CBD Oil and Antibiotics
There is no known interaction between CBD and antibiotics, although these interactions may occur if an antibiotic is metabolized through the cytochrome P450 enzyme system. Some studies indicate that taking CBD and antibiotics together may amplify the effects of one another without any negative side effects. However, more research is needed to confirm these findings on a larger scale.
CBD Oil and Omeprazole
CBD can inhibit the enzymes that are targeted by omeprazole and other Proton Pump Inhibitors (PPIs). Taking CBD with certain heartburn medications can increase the risk of diarrhea.
CBD and Thyroid Medications
Some people report mild nausea when taking CBD oil together with their thyroid medications. Since both substances are processed by the CYP450 enzyme system, taking CBD with a thyroid medication may cause hyperthyroidism because more thyroxine would be secreted than the body could metabolize.
CBD and Lisinopril
CBD can temporarily lower blood pressure, so taking it alongside medications like Lisinopril might reduce it even more, making you feel lethargic and weak. Always consult your doctor before adding CBD to your routine if you use anti-hypertension meds.
CBD and Prednisone
Since both CBD and corticosteroids are potent inhibitors of the CYP450 enzyme system, concomitant use may increase the risk of systemic side effects from corticosteroid use due to decreased glucocorticoid clearance. Corticosteroids like prednisolone and hydrocortisone should never be taken with CBD.
How Drugs Interact: Understanding Drug Metabolism
Metabolism can refer to how your body uses energy for weight management, or the way drugs are metabolized in your body.
The former is known as the basal metabolic rate, or in simple terms, the number of calories a person needs to maintain healthy body functions while at rest.
The latter is very different from the basal metabolic rate. Drug metabolism refers to how a substance is processed and used by the body — with the majority of this processing happening in the liver.
Scientists call it the ‘first-pass effect’ or ‘first-pass metabolism.’
Using straightforward terms, when you take a medication, it is broken down in the liver into its active compounds so that the body can use them. Just like carbohydrates are broken down into sugars, fats into triglycerides, and proteins into amino acids — drugs break down into their individual ingredients.
From there, they are controlled by specific enzymes, which transform these compounds into metabolites. These metabolites then influence different processes in your body and are flushed with urine once used up.
How Is CBD Metabolized?
Drug metabolism determines the rate at which the body processes medications and other therapeutic compounds into their individual metabolites and how long they can stay in your system.
When you take CBD in the form of an oil, capsule, or gummy, it has to pass through your gut, where it is released into the bloodstream. From then, they travel through the bloodstream to the liver, where it absorbs through the hepatic portal. The liver breaks CBD down into its metabolites using enzymes, after which it can circulate throughout the body in the bloodstream again.
What Is the Cytochrome P450 System?
Aside from breaking compounds down into metabolites, the liver also detoxifies and excretes foreign substances and other types of toxic compounds. This can happen through a system of enzymes referred to as the Cytochrome P450 (CYP450). These enzymes contain heme as a cofactor to convert cannabinoids into more water-soluble molecules, increasing their absorption and efficacy.
Researchers estimate that the CYP450 system is responsible for metabolizing 60% of any drugs out there. And interestingly, doctors and pharmacists use this system to understand, evaluate, and predict the benefits of the drug and potential side effects based on their dosages.
However, certain compounds have the ability to compromise the CYP system’s functioning, negatively affecting the metabolism of certain medications. Once these interactions occur, the drugs can be metabolized faster or slower than normal.
CBD And the Cytochrome P450 System
As mentioned earlier, CBD can interact directly with the CYP450 system in the liver. According to preclinical studies, CBD binds to the site where the enzyme activity occurs, competing with other compounds and thus preventing this system from breaking down other substances.
This inhibitory effect on the CYP450 enzymes mainly depends on how much CBD a person takes, their unique physiology, and the type of CBD used (e.g., full-spectrum CBD vs. CBD isolate). The dosage determines the strength used by the CBD to bind to the active site of the metabolic enzymes. The tighter the bond, the more competitive inhibition.
Contraindications for Taking CBD with Medications
The mechanism behind CBD’s health benefits proves that it’s not a biologically inert compound. Instead, the pharmacokinetics and pharmacodynamics of CBD are complex and similar to any other medication. Therefore, it has the potential to compromise the metabolism of certain medications.
Any therapeutic substance that relies on the CYP450 system can be potentially affected by CBD. A common indicator for such interaction is when your medication has a grapefruit warning on the bottle. However, this is by no means a solid point of reference, and you should always check with your doctor and pharmacist before taking the two compounds together.
Why You Should Always Consult Your Doctor First
The list of drugs that we’ve mentioned above is by no means definite and doesn’t include all the pharmaceutical substances that may interact with CBD. Similarly, not all the medication from these categories will necessarily cause an interaction — as is the case for antibiotics and Ibuprofen.
A consultation with a doctor experienced in CBD and cannabis use can help you establish the right routine for your medications and supplements to avoid potentially negative interactions. Some compounds work synergistically with CBD, so asking your doctor can help you maximize the effect of your treatment.
Not to mention that the doctor can guide you on finding the optimal dosage for yourself.
Key Takeaways on CBD Drug Interactions
The safety profile of CBD has been acknowledged by major health agencies, such as the World Health Organization (WHO), showing that it’s well-tolerated by animals and humans and rarely produces any dangerous side effects.
CBD also has a profound impact on an array of systems, which explains its therapeutic versatility. That being said, this versatility is also the reason why CBD interacts with so many prescription meds and over-the-counter (OTC) PRODUCTS.
Again, if you’re not sure if CBD will interact with the medication that you might be taking, a consultation with a health professional will not harm — unlike trying to figure out these interactions on your own.
Livvy is a registered nurse (RN) and board-certified nurse midwife (CNM) in the state of New Jersey. After giving birth to her newborn daughter, Livvy stepped down from her full-time position at the Children’s Hospital of New Jersey. This gave her the opportunity to spend more time writing articles on all topics related to pregnancy and prenatal care.