Found in various forms from oils and tinctures to lotions and gummies, CBD continues to become more accessible and has been growing in popularity in recent years. People have been turning to the incredible holistic supplement to help with a variety of different health issues and medical conditions, including anxiety, pain, insomnia, inflammation, and seizures.
CBD has very few side effects and as long as its THC level is under the legally required .3% as per FDA guidelines, it is non-intoxicating and non-psychoactive in its effect on its user. While the vast majority of research shows CBD oil is safe to use on its own, it is a powerful biological compound that interacts with various systems within the body. Therefore, CBD can have unintended and potentially serious consequences when combined with pharmaceutical drugs, supplements, or other substances.
Let's dive deeper into how CBD can potentially interact with other medications.
How Does Metabolism Play a Role in CBD’s Interactions with Other Medications?
Before we dive into CBD interactions with medications, it's essential to understand a few things:
How the body's metabolism functions in general
How CBD is metabolized in the body
The systems involved in the metabolization of CBD
How CBD affects the Cytochrome P-450 system
How Our Body's Metabolism Works
A lot of people think of metabolism in association to how easily or slowly your body is able to gain or lose weight. However, this is actually called the basal metabolic rate, or the rate in which your body uses energy while at rest to keep up with basic functions (breathing, staying warm, etc.).
Metabolism refers to a process in which various substances such as food, are broken down and used by the body. When you eat food, your liver will break it down into individual compounds to be processed by your body to be used for different purposes.
How CBD is Metabolized and What Systems are Involved
CBD metabolizes in the liver using cytochrome P450 isoenzymes and is stored in the fatty tissues for up to four weeks.
CBD is slowly released at sub-therapeutic levels back into the bloodstream and metabolized by your biliary and renal systems. The main primary metabolite of CBD is 7-hydroxy-cannabidiol.
CBD and the Cytochrome P-450 System
CBD can suppress activity of the cytochrome P450 enzyme, a crucial enzyme which is involved in the process of metabolizing many drugs. Certain compounds in grapefruit are also indicated to present with similar effects on this enzyme group.
As a result, physicians often advise patients not to eat grapefruit shortly before or after taking certain medications. By hindering activity of the cytochrome P450, CBD can either reduce or increase the effects of other drugs.
Some medications that have a grapefruit warning include:
blood pressure medications
(This is not a complete list, so consult with your healthcare provider in regards to grapefruit warnings for your current medications.)
Increasing the Severity of Potential Side Effects
CBD does have some potential side effects when taken on its own, such as drowsiness, lightheadedness, nausea, diarrhea, and dry mouth. Combining CBD with other medications that share the same side effects raises your risk of experiencing unwanted symptoms.
Some examples of drug interactions with CBD are:
Taking CBD simultaneously with an antihistamine, like Benadryl, can lead to increased tiredness and fatigue.
Increased sedation and sleepiness may also occur when using certain supplements, such as melatonin.
CBD used in combination with a stimulant, like Adderall, may lead to decreased appetite.
Certain heartburn and diabetes medication mixed with CBD can increase the risk of diarrhea.
CBD Can Alter Effects of Other Drugs
Enzymes have an important role in helping to break down many medications in the liver, and CBD may compete with or interfere with these enzymes if taken in combination with another drug. CBD’s interference with these enzymes can alter the concentration of drugs, meaning that the body can potentially absorb too much or not enough of a drug. As a result, the efficacy of the medication may weaken or the risk of side effects can be increased.
Is Everyone at Risk for CBD Drug Interactions?
Our liver and kidneys tend to eliminate drugs more slowly from the body as we age, which can increase the possibility of interactions between CBD and other drugs. In addition, older adults and people with chronic health problems are more likely to be using multiple medications to treat their various health issues. Therefore, the more medications you take, the higher your risk for experiencing potential drug interactions with CBD. While these factors can increase the chances of drug interactions, it is advised that everyone, regardless of their age or current health, should always first consult with a doctor or healthcare provider before beginning use of a CBD product.
Does Using a CBD Topical Oil or Cream Reduce the Risk of Drug interactions?
There is ongoing research that is studying the effects of how much topical CBD gets absorbed into the system as opposed to CBD taken through other delivery methods such as orally or through smoking or vaping. As there are other factors that need to be considered such as the active ingredients in the cream and where it's applied to the body, it can be challenging to determine CBD topicals’ potential for drug interactions.
Drugs That Can be Contraindicated For Use with CBD
Pennsylvania State University published a list of 57 drugs in which CBD can potentially cause severe or dangerous interactions due to its altering the concentration of the drug, including a wide variety of drugs ranging from antibiotics to heart medication.
Potentially severe interactions with CBD can occur with the following drug/ drug types:
Warfarin (blood thinner)
Fentanyl (narcotic for pain)
Levothyroxine (thyroid medication)
Clonidine (high blood pressure)
The above list is by no means comprehensive and does not include all medications with which CBD can potentially interact. Therefore, it's critical that you consult with your physician or healthcare professional before using any CBD product and provide them with a complete list of current medications you are taking to ensure incorporating CBD use into your regimen will be safe.