Pharmaceutical Drugs That Can Interfere with CBD

person Larry Ostrovsky
calendar_today Oct 28, 2017

How can CBD enhance and inhibit something simultaneously? That is the question medical teams are trying to address in cannabidiol (CBD) research today. The cannabinoid long has been known to inhibit the breakdown of compounds in the liver, but only recently have the intricacies of this counteraction become apparent.

On one hand, some studies have found CBD may enhance the strength of pharmaceutical drugs by increasing their presence in the bloodstream. On the other hand, it may prevent prescription drugs from being properly processed in the liver. Are you confused yet? So, too, are most researchers.

An Introduction to Cytochrome P450

The first step to understanding the complexities of drug interactions with CBD is understanding the group of liver enzymes called cytochrome P450. But first, a few basic biological facts.

The liver is almost always the processing point for pharmaceutical drugs. It metabolizes chemical compounds to cleanse the body of toxins, and transforms certain things into different composites for use later. For instance, the liver converts THC into THC-COOH, and CBD is transformed into 7-OH-CBD and 6-OH-CBD. Researchers still are relatively unsure what the CBD metabolites do. However, these transformed cannabinoids typically are stored in fatty tissues.

Cytochrome P450 is a group of liver enzymes responsible for processing anywhere from 60 to 80 percent of prescription drugs, depending on what study you reference. They also metabolize cannabinoids, such as CBD, CBN, and THC.

Long story short, the intricacies of the metabolization process are complicated. The basic premise consists of taking a compound, such as CBD, and incorporating an additional atom. When it comes to the cytochrome P450 family of enzymes, they rely on an oxidization process and incorporate an oxygen molecule into the mix.

How Does Cytochrome P450 Process CBD?

Imagine the cytochrome P450 enzymes as small molecular funnels in your liver. Compounds such as prescription drugs are directed into these funnels and slowly are metabolized into other compounds by the time they exit. A funnel’s processing time always is slow due to its cone-like shape. Despite how many may enter, only a small amount can exit at a time.

As mentioned earlier, the majority of prescription drugs are processed by the cytochrome P450 enzymes. However, once CBD enters into the body, it essentially takes over the processing time and function of this enzymatic funnel. Cannabidiol plugs the conduit and takes over all metabolization. It prevents other chemical compounds from a reasonable and timely transformation. For reasons researchers still are trying to figure out, CBD demands all the attention and inhibits cytochrome P450 from metabolizing all other chemical compounds.

Researchers believe cytochrome P450 is responsible for metabolizing all cannabinoids, and have researched the method for CBD, THC, and CBN. So far, CBD has been found to be the strongest cannabinoid inhibitor of normal enzyme processing.

Interactions between CBD and Pharmaceuticals

At this point, you likely are thinking, "What if my liver enzymes don’t process pharmaceutical drugs? Isn’t it always said you pee out anything you don’t use?” Unfortunately, this is not the case with most prescription drugs. If your body cannot metabolize a prescription drug, because it is too busy processing CBD, the medicine may build up to toxic levels in your bloodstream. Not surprisingly, this is still a very preliminary theory.

For example, one study on the use of CBD with epilepsy patients found that, depending on dosage, CBD inhibited the metabolization of anti-seizure drugs already prescribed to the patient. Some studies suggest that doctors should assess the toxicity (or level of medication) found in the blood, and reduce the anti-seizure drugs as needed. However, this is where it starts to get complicated and untested.

Other studies have looked at the counteraction between CBD therapy and epilepsy drugs and found it to be extremely dose-dependent. Lower doses of CBD serve no purpose for controlling the disease. Instead, researchers concluded lower doses only prevented the anti-seizure drugs from functioning correctly. In response to this, some physicians have recommended using only high doses of CBD for epilepsy to reap the full benefits.

As you can see, the only thing scientists can agree on is CBD may inhibit and/or enhance the productivity of cytochrome P450. The results and potential risks are believed to vary greatly depending on individual circumstances.

It should be emphasized at this point that these hypotheses remain untested in clinical trials. They only should be considered as ideas worth further scientific exploration.

Some Prescriptions that may Interact with CBD

These interactions have not been extensively studied. However, if you take any of the following types of prescriptions, it's best to seek a professional opinion if you wish to begin CBD supplementation. A doctor may recommend different dosages than you normally would be prescribed, or may make other changes to your medication regime. This list is not comprehensive.

Antibiotics
Anesthetics
Beta blockers
Sulfonylureas
Anti-depressants
Anti-epileptics
NSAIDs
Oral hypoglycemic agents
Antihistamines
HIV antivirals
Immune modulators
Benzodiazepines
Anti-arrythmics
Anti-psychotics

More Clinical Research is Needed

At the moment, researchers only have explored how CBD isolates interact with the metabolism of pharmaceutical drugs. Many of their conclusions have yet to be proven.

For example, cancer patients who are undergoing chemotherapy treatment often rely on cannabis and cannabinoids to mitigate side effects. But chemotherapy is a careful combination of complex chemicals meant to kill cancerous cells. Can CBD potentially inhibit the metabolization of the chemotherapy drugs? Could it lead to an increased toxicity of these drugs in the bloodstream?

This particular interaction hasn’t been studied yet, but patients seeking to combine CBD with chemotherapy treatment always should speak with their medical team. More research is needed to determine what circumstances lead to counteractive effects, and with what medications. If you are interested in exploring CBD, but already are taking prescription drugs, it is strongly recommended to discuss this with your doctor beforehand. It's essential to monitor the level of medications in your bloodstream, and re-adjust dosages as needed.