Products containing cannabidiol (CBD) are very popular, promising relief from a wide range of maladies. But if you are considering taking a product containing CBD, be aware that if you are taking any other prescription or over-the-counter medications, supplements, or herbal products, CBD can interact with them and cause unexpected … In our latest question and answer, the pharmacist discusses the use of CBD with Lamictal and Prilosec. CBD Medical Interactions. What’s safe? As CBD becomes more popular in the healthcare industry, you should be informed on CBD medical interactions and other safety concerns. Because
CBD and other medications: Proceed with caution
Products containing cannabidiol (CBD) seem to be all the rage these days, promising relief from a wide range of maladies, from insomnia and hot flashes to chronic pain and seizures. Some of these claims have merit to them, while some of them are just hype. But it won’t hurt to try, right? Well, not so fast. CBD is a biologically active compound, and as such, it may also have unintended consequences. These include known side effects of CBD, but also unintended interactions with supplements, herbal products, and over-the-counter (OTC) and prescription medications.
Doubling up on side effects
While generally considered safe, CBD may cause drowsiness, lightheadedness, nausea, diarrhea, dry mouth, and, in rare instances, damage to the liver. Taking CBD with other medications that have similar side effects may increase the risk of unwanted symptoms or toxicity. In other words, taking CBD at the same time with OTC or prescription medications and substances that cause sleepiness, such as opioids, benzodiazepines (such as Xanax or Ativan), antipsychotics, antidepressants, antihistamines (such as Benadryl), or alcohol may lead to increased sleepiness, fatigue, and possibly accidental falls and accidents when driving. Increased sedation and tiredness may also happen when using certain herbal supplements, such as kava, melatonin, and St. John’s wort. Taking CBD with stimulants (such as Adderall) may lead to decreased appetite, while taking it with the diabetes drug metformin or certain heartburn drugs (such as Prilosec) may increase the risk of diarrhea.
CBD can alter the effects of other drugs
Many drugs are broken down by enzymes in the liver, and CBD may compete for or interfere with these enzymes, leading to too much or not enough of the drug in the body, called altered concentration. The altered concentration, in turn, may lead to the medication not working, or an increased risk of side effects. Such drug interactions are usually hard to predict but can cause unpleasant and sometimes serious problems.
Researchers from Penn State College of Medicine evaluated existing information on five prescription CBD and delta-9-tetrahydrocannabinol (THC) cannabinoid medications: antinausea medications used during cancer treatment (Marinol, Syndros, Cesamet); a medication used primarily for muscle spasms in multiple sclerosis (Sativex, which is not currently available in the US, but available in other countries); and an antiseizure medication (Epidiolex). Overall, the researchers identified 139 medications that may be affected by cannabinoids. This list was further narrowed to 57 medications, for which altered concentration can be dangerous. The list contains a variety of drugs from heart medications to antibiotics, although not all the drugs on the list may be affected by CBD-only products (some are only affected by THC). Potentially serious drug interactions with CBD included
- a common blood thinner, warfarin
- a heart rhythm medication, amiodarone
- a thyroid medication, levothyroxine
- several medications for seizure, including clobazam, lamotrigine, and valproate.
The researchers further warned that while the list may be used as a starting point to identify potential drug interactions with marijuana or CBD oil, plant-derived cannabinoid products may deliver highly variable cannabinoid concentrations (unlike the FDA-regulated prescription cannabinoid medications previously mentioned), and may contain many other compounds that can increase the risk of unintended drug interactions.
Does the form of CBD matter?
Absolutely. Inhaled CBD gets into the blood the fastest, reaching high concentration within 30 minutes and increasing the risk of acute side effects. Edibles require longer time to absorb and are less likely to produce a high concentration peak, although they may eventually reach high enough levels to cause an issue or interact with other medications. Topical formulations, such as creams and lotions, may not absorb and get into the blood in sufficient amount to interact with other medications, although there is very little information on how much of CBD gets into the blood eventually. All of this is further complicated by the fact that none of these products are regulated or checked for purity, concentration, or safety.
The bottom line: Talk to your doctor or pharmacist if using or considering CBD
CBD has the potential to interact with many other products, including over-the-counter medications, herbal products, and prescription medications. Some medications should never be taken with CBD; the use of other medications may need to be modified or reduced to prevent serious issues. The consequences of drug interactions also depend on many other factors, including the dose of CBD, the dose of another medication, and a person’s underlying health condition. Older adults are more susceptible to drug interactions because they often take multiple medications, and because of age-related physiological changes that affect how our bodies process medications.
People considering or taking CBD products should always mention their use to their doctor, particularly if they are taking other medications or have underlying medical conditions, such as liver disease, kidney disease, epilepsy, heart issues, a weakened immune system, or are on medications that can weaken the immune system (such as cancer medications). A pharmacist is a great resource to help you learn about a potential interaction with a supplement, an herbal product (many of which have their own drug interactions), or an over-the-counter or prescription medication. Don’t assume that just because something is natural, it is safe and trying it won’t hurt. It very well might.
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:
CBD Medical Interactions. What’s safe?
As CBD becomes more popular in the healthcare industry, you should be informed on CBD medical interactions and other safety concerns.
Because cannabidiol, or CBD as it’s called for short, has anti-inflammatory and pain-relieving properties, many healthcare professionals are beginning to offer their patients products with this particular ingredient as a way to help relieve or resolve a variety of different issues.
However, because CBD comes from the cannabis plant often brings up a number of safety-related questions. Being knowledgeable about the safety-related issues of CBD can help you better inform your patients.
Will CBD products make my patients high?
If you’re concerned about CBD making your patients feel the high commonly associated with marijuana use, don’t be says Anthony Franciosi. Franciosi is a “ganja-preneur” and founder of the Honest Marijuana Company, a company which utilizes all-natural cultivation methods to produce organic and eco-conscious cannabis products, even packaging them in earth-friendly recyclable tin cans.
“CBD doesn’t seem to make people mind-alteringly high,” Franciosi explains, “because it has very little effect on the CB1 receptors in the brain that regulate learning, coordination, sleep, pain and CB2 receptors in the immune system.”
Thus, patients exposed to CBD in health-related products such as oils, lotions, and creams, don’t have to worry about this type of effect.
Will CBD products make my patients sleepy?
Another well-known side effect of cannabis is how it relaxes the user, potentially causing some concern that patients using CBD products will notice this same impact, rendering them unable to live an active life during its use.
Rachna Patel is a medical marijuana doctor based out of Walnut Creek, California and she says that this isn’t an issue. Specifically, Patel says that, when it comes to topicals containing CBD, they “tend to not cause the same side effects as medical marijuana products that are inhaled, ingested, or used sublingually, like the high or drowsiness.”
Therefore, your patients can use these types of products without fear of any type of tiredness or lethargy as a result.
What about drug interactions?
Drug interaction is a huge issue as combining two or more substances that shouldn’t be taken at the same time can sometimes result in unintended side effects. For example, it can “make your drug less effective, cause unexpected side effects, or increase the action of a particular drug,” says the U.S. Food and Drug Administration. In some cases, it can even be deadly.
CBD is known to reduce the levels of Lamotrigine and enhance the effects of Clobazam so be sure to check with your patients what medications they are taking before recommending CBD products.
When is CBD potentially unsafe for patients?
Patel does advise that there are a couple of instances in which CBD should not be used for patient care. An allergy to CBD is one of them.
“I generally suggest that patients check the ingredients on the label to ensure that they are not allergic to any of the ingredients listed. Also, topicals based in an alcohol can exacerbate certain skin conditions like psoriasis, for instance.”
How do I find the safest CBD products possible?
Gunhee Park, founder of Ministry of Hemp, warns that there are currently no quality measures in place when it comes to CBD products. “As of now, it’s really up to individual companies to police themselves and operate transparently,” he says. That being said, there are still some steps you can take to ensure that you offer your patients the safest CBD products possible.
For starters, pay attention to the origin of the oils, says Park. “The main reason why hemp’s cultivation environment is so important,” he explains, “is because of hemp’s properties of absorbing contaminants from the soil while it grows. So if the soil it was grown on is not good, clean soil, then that plant might contain high levels of lead or mercury.”
Park also suggests that you “always request third party lab results on the products. These lab results should test for potency, pesticides, residual solvents, and mycotoxins of the CBD hemp oil.” According to Park, obtaining these third-party results “are the only way to ensure a clean or safe product.”
Additionally, when it comes to CBD topicals, Park says that it’s important to take the time to check the label to ensure that it has a transdermal delivery system. This includes looking for keywords like “nano technology, encapsulation, or micellization of CBD. This shows that their solution can carry CBD through the dermal layers.”