What Drugs Should Not Be Taken with CBD

What Drugs Should Not Be Taken with CBD

It is widely acknowledged that CBD has few side effects, and even those are less than adverse. There are, however, concerns how CBD’s interaction with other drugs would affect the user’s body. It is for this reason that you need to know which drugs you shouldn’t use alongside CBD.

The kind of drugs that would be right to use alongside CBD are the ones whose functions it can’t affect. This means that the drugs would be just as effective even after taking them alongside CBD.

You should also avoid using any drugs that would negate the expected effects of CBD on the user’s body because then you wouldn’t benefit from the effects of CBD. The worst-case scenario, however, is if CBD reacts with the drug in question to cause the user harm. It is also noteworthy that the formulation of CBD being used plays a significant role in informing the effect. CBD capsules may be affected more by the interaction than other formulations.

All these scenarios should be avoided by not using CBD alongside other drugs. This article seeks to show you which drugs should not be taken with CBD. It achieves this by giving necessary information on how drugs get metabolized and how the metabolism may be affected by the use of CBD.  

What is metabolism?

The understanding of metabolism as it is in the public domain is different from what it means. Most people understand metabolism as the number of calories they need for their bodies to function effectively.

Metabolism refers to the process of breaking down substances such as food and drugs that get into the body. They need to be broken down into forms that the body can absorb, and it is only after absorption that they can have the intended effects on the body. Understanding metabolism is vital to the general understanding of how CBD interacts with the body alongside other drugs. 

Most of the metabolism processes occur in the digestive system. The gut is highly adapted for that purpose. Many substances we take, need to go through the liver in a process commonly referred to as the first-pass metabolism.

Different types of foods and other substances are usually broken down in the liver into metabolites. As metabolites, the substances are in a form that can be used for the purposes it is intended for. Each food group produces more than one metabolite, and each metabolite has a role to play in the body.

Drug Metabolism

Just like food, the active ingredients of a drug can only be useful to the body after it has been broken down. Once taken through the mouth, the metabolism process has to start in the gut, but the liver plays a very significant role in breaking the medicine down.

More extensive involvement of the liver happens with all therapeutic products that get into the body. This is because the substances typically contain a lot of foreign substances that the body can’t synthesize. The liver plays the role of converting these foreign substances so that they can easily be excreted from the body. 

The chemical changes through which the unusable substances are changed in the liver are known as biotransformation.

Drug metabolism occurs in two phases, which are simply referred to as Phase I and Phase II.

In Phase I, the liver, through oxidation, alters the chemical structure of the medication. This modification is such that the drug is broken down into metabolites, but it retains its pharmacological properties. Retention of pharmacological properties means that the metabolites have the same effects on the user, both physiologically and psychologically. 

In Phase II, substances intended to be excreted from the body are combined with other molecules through the process of conjugation. Once conjugated, the target material becomes pharmacologically inactive and also soluble in water. These two attributes make the substance easy to flash out of the body.

Cytochrome P450 System

The Cytochrome P450 system is a group of enzymes that help to make fat-soluble substances more water-soluble. This change makes it possible for the substances to be absorbed in the body for use and excretion. The enzymes are the ones that metabolize drugs, and they are also referred to as the CYP system.

The CYP system is central to the metabolism of more than 60% of all drugs taken. It is for this reason that doctors can use a person’s CYP system to calculate the appropriate dosage for any drug. They calculate the dosage by observing the time it takes for a healthy liver to metabolize a drug.

The interaction between the CYP and some substances causes it to slow down in its metabolism of drugs. When the CYP slows down, one may end up taking the next dose of the medication while the previous dose has yet to be broken down. This would mean more of the drug’s active ingredients in the system at any given time than was previously anticipated at prescription. In the end, this might have adverse effects on the user’s body. CBD is one of the substances that have been found to slow down the CYP system. 

CBD connects with the CYP enzymes, a competitive inhibitor. By connecting competitively with the enzymes, it displaces other drugs that need to be broken down in the system. This keeps the drugs from being utilized or excreted as quickly as they should. The level to which CBD slows down the process of drug metabolism depends on factors such as how much CBD is in the system.

These levels usually depend on the concentration of the cannabinoid in the CBD product taken. You could, for example, have taken several CBD capsules but not have as much CBD in the system as when you take a smaller amount of a concentrate with a much higher concentration of CBD.  

It is important to note that the CBD oils and tinctures usually have little or no effect on the liver because they are usually taken sublingually. Once taken, they get absorbed directly into the bloodstream without having to go through the first-pass metabolism. Other formulations, such as CBD dermal patches, also bypass the first pass process. 

If you take large amounts of CBD when using other medications, the drug may not work well because a considerable amount of the other drug will not be metabolized. In some instances, reduced effectiveness of drugs might manifest in the form of blood’s diminished ability to clot. The user’s immune system may also be negatively affected by this interaction between CBD and the CYP enzymes.

CBD and Drug Interactions: Contraindications

In medicine, a contraindication refers to circumstances in which a drug becomes harmful to the user, and it, therefore, should be used. In this instance, we are looking at the circumstances in which CBD’s potential interaction with drugs can be a reason for a doctor not to prescribe the medicine in question.

The following is a list of other drugs that can be contraindicated due to being used alongside CBD. 

Steroids and Corticosteroids

Some of the drugs that fall under this category include cortisone, triamcinolone, and prednisone, among others. They are typically prescribed for the management of inflammation, especially in the respiratory system. CBD may have the same effect as these drugs on the body, and the outcome of taking both CBD and the steroids may be such that the body may react in the same way as when it has an overdose of steroids.

Calcium channel blockers

Examples of common drugs that fall under this category include amlodipine, isradipine, and nifedipine, among others. These drugs are used for the management of high blood pressure, irregular heartbeats, and chest pains. They keep calcium from getting into the cells of the heart and arteries, which helps them to relax. These drugs may exacerbate the adverse effects of CBD, such as body lock, and one should be cautious when using both of them. 


These are drugs that dilate the airways in the respiratory system. They are typically prescribed for people with conditions such as asthma. When CBD is smoked or vaped by people who use bronchodilators, it reduces their effects on the user. A patient, therefore, should stop using CBD while on these drugs so that they can have the exact effect that was intended at prescription.


Some of the standard antidepressants in the market include citalopram, vilazodone, and escitalopram, among others. Some research findings indicate that when taken alongside antidepressants, CBD is likely to cause irritability in users. One may, therefore, take the best CBD oil for anxiety and depression and not end up any happier.


Some of the common drugs that fall under this category are Xanax and Ativan. This medication is used to treat anxiety. When used alongside CBD, their common side effects, such as drowsiness, may become even more severe. In some instances, the combination may sedate the user. Due to the slowed metabolism at the CYP system attributed to CBD, benzodiazepines may increase to such levels in the body that they become toxic. Their toxicity typically affects the respiratory system.


Some antibiotics, such as Aleve, Advil, Amoxicillin, and azithromycin, among others, may be altered from their interaction with CBD.


These are substances that must first be metabolized to become therapeutic compounds. This means that in their original state, they are not medicine; they only became useful to the body for therapeutic purposes after they are broken down. This process usually depends on the CYP system, whose activity is usually inhibited by the use of CBD. It means, therefore, that if CBD when the two are used together, the body won’t benefit sufficiently from the metabolites coming from the prodrug. 

Potential Drug Interactions

One of the drugs that may typically be prescribed alongside CBD is Clobazam. This is because Clobazam is often a part of the regimen used to treat children with seizures, and CBD is also used to treat the same condition. CBD causes an increase of Clobazam in the system, the intended dosage. The heightened clobazam levels may cause an overdose on the user in the long run.

CBD also has the same effects on Warfarin, an anticoagulant. It increases the amounts of Warfarin in the body, which may end up causing excessive bleeding. A person using this drug should, therefore, either take only small amounts of CBD or avoid CBD all together when on Warfarin.

Research on CBD and its effects on the body is still ongoing. This means that there could still be many effects that are yet to be understood.

The safest way to approach the interaction between CBD and medicine is by looking out for the ‘grapefruit warning.’ This is a warning that is typically found on the label of some drugs. It warns the patient no to take grapefruits or grape juices when using the medicine. The reason for this warning is because the drugs interact with grapefruit in a manner that may cause them problems.

There are more than 85 medicines that similarly interact with grapes, like CBD. They inhibit the proper function of the CYP system. The similarity between CBD and grapefruit in terms of their effects on the liver means that people should avoid using CBD alongside drugs that have grapefruit warning.

Drugs that have this grapefruit warning are used in the management of some problems in which CBD is used. Some of them are antiepileptic drugs, and CBD also helps with the management of seizures. Mood medications and antidepressants may also fall into this category. It is, therefore, important for careful consideration to be given on dosage if both CBD and the drugs will be used to manage these conditions. Users should always disclose their usage of CBD to their doctors.

Key Takeaways

CBD is readily available in the market in different formulations today. It comes in the form of the best CBD gummies, capsules, and CBD oil, among other formulations. Users should, therefore, be careful before using the CBD alongside drugs, especially when the CBD formulation goes through the first-pass process.


Dwight K. Blake Written by: Dwight K. Blake

Dwight was a Mental Health counselor at Long Island Psychotherapy & Counseling in Westbury, New York for more than 15 years. He believes that CBD is the prime solution to this mental illness and more-- with proper research, medical acknowledgment, and application.
Through his work at AmericanMarijuana, together with the rest of the team, he wishes to provide everyone with genuine results and high-quality product reviews for everyone to enjoy for free.

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