Statins are processed by CYP function in the liver, which CBD inhibits. While no research has specifically studied interactions between statins and CBD, the cannabinoid could potentially increase the strength and duration of statins in the system and the risk of unwanted side effects.
Metformin is a medication prescribed to adults with type 2 diabetes to help control blood sugar levels. Side effects of metformin include low blood sugar, nausea, diarrhea, vomiting, and muscle pain.
Cannabis is a complex plant, with hundreds of chemicals and over 100 distinct cannabinoids. The little research that examines cannabidiol or CBD, the second most common cannabinoid found in cannabis, shows evidence of potential health benefits for a wide range of conditions. As CBD becomes more mainstream, however, a key question comes to mind, “How will CBD interact with my current medication?”
Drugs that should not be taken with CBD
Warfarin, also known under the brand name Coumadin, is an anticoagulant (blood thinner) medication used to prevent the formation of harmful blood clots that could potentially cause heart attacks or strokes. Warfarin’s risks include severe bleeding, headaches, swelling, or sudden pain in extremities.
Statins are a classification of drugs designed to lower cholesterol and protect against heart attack and stroke. Common side effects of statins are muscle soreness, blood sugar increase, headaches, and nausea.
Clobazam, used to treat epileptic seizures, is another type of drug that may not be advisable to take in conjunction with CBD. However, Epidiolex is an FDA-approved, CBD-based drug that physicians may prescribe to treat epilepsy. A significant amount of data, derived from clinical trials, exists on Epidiolex, although the drug can also cause adverse effects, according to a 2019 study conducted by researchers at Columbia University and published in the journal F1000Research.
Acetaminophen, the generic name for Tylenol, is a common drug used for pain and fever relief. Acetaminophen carries a risk of liver damage and disease, with side effects including nausea, headaches, and insomnia.
It’s illegal in the U.S. to market CBD by adding it to any food or calling it a dietary supplement. Also, although the FDA has approved a few CBD drugs to treat certain diseases, don’t expect CBD sold over the counter to be safe or beneficial for heart failure, Lundgren says.
ClinicalTrials.gov: “Cannabidiol in Patients With Heart Failure in AHA/ACC Stages A-C (CAPITAL-AC).” NCT03634189.
What We Know About CBD
FDA: “What You Need to Know (And What We’re Working to Find Out) About Products Containing Cannabis or Cannabis-derived Compounds, Including CBD,” “FDA Approves First Drug Comprised of an Active Ingredient Derived from Marijuana to Treat Rare, Severe Forms of Epilepsy,” “FDA and Cannabis: Research and Drug Approval Process.”
JCI Insight: “A single dose of cannabidiol reduces blood pressure in healthy volunteers in a randomized crossover study.”
When you use CBD oil, your liver breaks it down. During this process, it could interfere with your medications for heart failure or other heart conditions. “CBD has known interactions with warfarin, certain statins, calcium channel blockers, beta-blockers, and nitrates. Just because a supplement is ‘natural’ doesn’t mean that it is safe,” Lundgren says.
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.
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
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
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.
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.
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.
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.