CBD Drug Interactions: Mixing Cannabidiol and Medications

CBD, also known as cannabidiol, is the second most prevalent active ingredient in cannabis (marijuana). It has been popularly touted as a good booster for your post-workout smoothie or morning coffee. It also 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. If you are considering using CBD, we highly recommend you talk to your doctor.

CBD Drug Interactions

How does CBD Interact with Medications?

While CBD generally is safe, it has side effects that include drowsiness, lightheadedness, nausea, diarrhoea, dry mouth, and, in rare instances, damage to the liver. When CBD interacts with medications that have similar side effects it, it can cause more toxicity to the body. 

Taking CBD at the same time with OTC or prescription medications and substances that induce sleepiness causes increased sleepiness, fatigue, and possibly, dangerous accidents. If you take CBD and Adderall together, it leads to decreased appetite; the same applies to taking CBD with stimulants. If you pair CBD and metformin together or with certain heartburn drugs (such as Prilosec), there is a high risk for diarrhoea. 

Can CBD Alter the Effects of Drugs?

Yes, CBD can alter the effects of drugs. According to Harvard Health Publishing, the enzymes in our liver break down many drugs. CBD may compete or interfere with these drugs, which leads to too much or not enough of the drug in the body (altered concentration). When you ingest CBD oil and oxycodone (or other opioids), you will experience heavy sleepiness and fatigue. 

What is the Current Research Situation on Interactions between CBD and Medications?

The current research situation takes most of its more reliable information from studies conducted on the only FDA-approved CBD product, Epidiolex. Epidiolex is commonly used to help treat epilepsy. 

According to Dr. Nina M. Bemben, PharmD, BCPS, a specialist in drug interactions, Epidiolex has been found to increase blood levels of the blood thinner warfarin by about 30% and interacts with other medications used for epilepsy. 

On the other hand, clinical trials have also been conducted. The study was conducted by Alexandra L. Geffrey, Sarah F. Pollack, Patricia L. Bruno and Elizabeth A. Thiele. Out of the 25 children in the study who had difficulty treating epilepsy, 13 kids were given both clobazam and CBD. Results showed that taking CBD and clobazam together is safe, but recommend monitoring medication levels due to side effects. 

What are the Common Types of Drugs Used with CBD?

The common types of drugs used with CBD are the following:

  • Antidepressants – Antidepressants can help relieve symptoms of depression, social anxiety disorder, anxiety disorders, seasonal affective disorder, and dysthymia, or mild chronic depression, as well as other conditions. Depression and mental health diseases are usually caused by chemical imbalances of neurotransmitters in the brain that are believed to be responsible for changes in mood and behavior. 
  • Heart medications – Heart medications such as ACE inhibitors and beta blockers, are usually prescribed by the doctor to help treat different forms of heart disease. ACE inhibitors help lower blood pressure and beta blockers block the effects of adrenaline so that the heart can work better. 
  • Macrolides – Macrolides are a class of antibiotics derived from Saccharopolyspora erythraea, a form of soil-class bacteria. Macrolides treat respiratory, skin, soft tissue, sexually transmitted diseases, H. pylori and atypical mycobacterial infections. Some macrolides include Clarithromycin and Biaxin. 
  • Drowsiness-inducing medications – Medications that can induce drowsiness come in many forms, such as allergy medications and muscle relaxants.  Allergy medications (antihistamines) can induce drowsiness for allergies, hives, nasal congestion, itchy rashes and sleep aid. Muscle relaxants are usually taken to treat muscle spasms and hyperreflexia.

What Drugs do Interact with CBD?

The drugs that interact with CBD, as indicated by researchers from Penn State College of Medicine and by Harvard Health Publishing, are:

  • Alfentanil – Alfentanil is an opioid. It is used to supplement general anesthesia for various surgical procedures and as an anaesthetic agent for cardiac surgeries. If you take CBD with Alfentanil, you may suffer from sleepiness and fatigue due to their similar side effects. 
  • Fentanyl – Fentanyl, like Alfentanil, is an opioid that interacts with CBD. It is a very potent opioid that is used as pain medication and often used recreationally. Due to its potency and opioid property, it’s dangerous to take it with CBD as it will lead to fatigue and sleepiness and may even cause accidents. 
  • Metformin – Metformin is a medication that helps treat type 2 diabetes, particularly in people who are overweight. It is also commonly used to treat Polycystic Ovary Syndrome, a reproductive and metabolic disease where its patient has high insulin resistance, hormonal problems and difficulty losing weight. According to CFAH.org, a health and wellness site, taking  Metformin with CBD may increase or decrease levels of the medication in your bloodstream. A side effect of ingesting CBD and Metformin is diarrhoea. 

Who are the most at Risk of CBD Drug Interactions?

According to research conducted by Joshua Brown and Almut G. Winterstein, those who are most at risk for CBD drug interactions are older adults, specific to children and adolescents with severe illness, and people with serious underlying indications for medical cannabis use.

The factors that affect their risk level for CBD drug interactions are:

  • Age – For several reasons, older people are at higher risk for CBD drug interactions. As we grow older, our bodies become slower at eliminating drugs from the body. Older people and patients tend to use multiple medications, which raises the risk for drug interactions. 
  • Physical and mental health problems – A common denominator for people at high risk for drug interactions is due to their health problems, which range from diseases like heart disease to mental health conditions such as anxiety. These health problems encompass physical and mental health. Some patients who suffer from great physical pain opt to use cannabis for pain management, while those with anxiety and depression use cannabis recreationally to treat their mental health conditions. 

What Side Effects and Diseases can be Occurred by CBD and Drug Interactions?

The side effects and diseases that can be occurred by CBD and drug interactions are:

  • Diarrhoea – Diarrhoea manifests through dehydration and loose stools. Acute diarrhoea usually lasts 1-2 days but it can last longer. If your diarrhoea lasts longer (chronic diarrhoea), it is usually a sign of chronic disease. 
  • Fatigue – Fatigue is characterized by a lack of energy and feeling of tiredness. It can cause employee performance to suffer due to poor and clouded judgement and affects people’s moods and behaviors. It has a vast range of symptoms. These symptoms include headaches, dizziness, poor concentration and chronic sleepiness. 
  • Sleepiness – Sleepiness is defined as difficulty staying awake. Sleepiness is especially problematic for working professionals and college students; a study on sleepiness conducted by Shelley D. Hershner and Ronald D. Chervin indicate that it can result in lower grade point averages, increased risk of academic failure, compromised learning, impaired mood, and increased risk of motor vehicle accidents.
  • Accidents – Accidents are a potential side effect from CBD and drug interactions. Due to CBD and drug interactions particularly doubling up the side effects of drugs that can induce sleepiness and fatigue, accidents may occur as a negative result. Accidents can be very delicate, as vehicular ones can take lives and paying for them medically is not easy on the wallet.

Is CBD Type Important in the Interaction of CBD and Drugs?

Yes. CBD Type is important in the interaction of CBD and drugs because different CBD types contain varying amounts and varieties of CBD and Tetrahydrocannabinol (THC). 

Based on findings from a study done by Tony Antoniou, Jack Bodkin and Joanne M.-W. Ho, Cannabinoid levels can both be increased by other medications and can affect levels of other drugs. Additive effects can also occur when marijuana is combined with other drugs. 

Is CBD Product Type Important in the Interaction of CBD and Drugs?

Yes, CBD product type is absolutely important in the interaction of CBD and drugs. CBD that is usually inhaled gets into the blood the fastest, which raises the risk for acute side effects. Edibles can require a longer time to absorb and are less likely to produce a high concentration peak but they are also capable of producing a concentration peak high enough to interact with other medications. 

Topical CBD, out of all the CBD product types, according to Dr Rachna Patel, DO, most likely has the least chances of being absorbed into your system.

Is CBD Dosage Important in the Interaction of CBD and Drugs?

Yes, CBD dosage is important in the interaction of CBD and drugs because there is a recommended dosage for CBD that is deemed safe for ingesting and because the after-effects and consequences of drug interactions is dependent on several factors, which include CBD dosage, according to Harvard Health Publishing.