What You Need To Know About CBD Interactions

While there is plenty to celebrate about the newest wave of CBD, consumers have a lot to learn.

Consumers are celebrating the possibility of physical and mental benefits from cannabidiol (CBD). How these compounds affect the body and mind are still under research.

Cannabis can accelerate or inhibit the effects of other drugs.

Although generally considered not harmful, cannabis is a drug. And like prescription medicines, it can cause drug-drug interactions, some of which can be harmful. Here, we look at some of these interactions.

While the users of CBD in any form might be experiences benefits, they should stay informed. These are the current known interactions with CBD and other compounds. 
How drugs interact

Enzymes metabolize most drugs in the liver. 


The liver is responsible for metabolizing an estimated 50% of prescription medications used in clinical practice.


These enzymes are also known to cause many clinically relevant drug-drug interactions. Some drugs induce the enzymes’ metabolic activity while others inhibit drug metabolism, which changes the concentrations of drugs present in the body as well as the ways they work. 


For example, a drug that inhibits certain liver enzymes will slow the metabolic process, resulting in an accumulation of drug concentrations and leading to an increased risk for side effects and possible drug toxicity.


Both THC and CBD are metabolized in the same way. 


When cannabis or CBD is used orally along with certain prescription drugs, THC and CBD can inhibit or induce the metabolic process. For example, CBD is a potent inhibitor of specific enzymes, while THC is an inducer of those same enzymes. 


Here’s a breakdown of medications known to have drug-drug interactions with CBD.


AlcoholAlthough not a prescription drug, alcohol is still a drug. As such, researchers have found that alcohol can increase the inebriating effects of cannabis. With CBD, however, all that is understood is that the liver breaks down the compounds in a similar way would perhaps diminish the ability of CBD to work to it’s fullest.  


Clobazam

CBD increases the effects and side effects of clobazam. The emerging research behind this interaction indicated that both of these compounds are successful in treating seizures associated with Lennox-Gastaut syndrome in children and adults. 


Instead of being contraindicated, CBD was found to be effective, making Episolex the first-ever marijuana-derived drug approved by the FDA.


Since CBD is so effective as a seizure inhibitor, the interaction contributes to clobazam’s efficacy, resulting in a three-fold increase of efficiency. The downside is that this interaction also increases clobazam’s side effect of sedation. As a result, clinicians are advised to lower the dose of clobazam when used in conjunction with CBD. 


Warfarin

New research has shown that the use of cannabinoids increases the risk of bleeding in patients taking warfarin.


Warfarin is known for the anticoagulant effect, but any changes to the way it interacts in the liver can increase the risk of bleeding and thrombosis. Because THC and CBD can inhibit the metabolic activity of the CYP2C9 liver enzyme, they can increase warfarin levels and thereby increase the risk of bleeding.


Valproate

Valproate is another drug prescribed to treat epileptic seizures, and it’s also indicated for treating manic episodes of bipolar disorder and for preventing migraine headaches.


Taking CBD with valproate can raise liver enzyme levels and may cause liver injury. In clinical trials, 21% of patients with epilepsy taking both valproate and prescription CBD (Epidolex) had elevated transaminase levels that were more than three times the upper limit of normal. (The incidence rate was 30% in patients with epilepsy taking concomitant CBD, valproate, and clobazam.)

The prescribing information for Epidolex recommends discontinuing or adjusting the dose of Epidolex and/or valproate if liver enzyme elevations occur.

More research is needed to understand the interactions of cannabis with these drugs further, as well as to discover its as-yet-unknown drug-drug interactions.