Nicky asked
I enjoyed reading your CBD interaction articles. What about with Prozac? It is safe to use with it?
Answer
There are no documented interactions between Prozac (fluoxetine) and CBD oil (cannabidiol). However, this is most likely due to the lack of data available as CBD has just recently begun growing in popularity as an over the counter supplement (and as a prescription product).
We have written a few articles concerning CBD drug interactions, including one with Zoloft, another SSRI like Prozac. It may be worth checking that article out for more information.
Below, we will discuss some important points regarding potential CBD interactions, including interactions concerning Prozac.
What Is CBD (Cannabidiol)?
- Cannabidiol, also known as CBD, is one of the major constituents of cannabis (i.e. marijuana).
- CBD makes up almost 40% of cannabis extracts and has a wide range of potential benefits when used medicinally, although more studies are certainly needed to better understand the compound and its potential health benefits. Nevertheless, it has been used for the treatment of:
- Anxiety
- PTSD
- Muscle spasms
- Chronic pain
- Epilepsy
- Multiple Sclerosis
- Insomnia
- Parkinson's Disease
- CBD is "non-euphoric" and does not cause a "high", unlike THC. Over the counter CBD products do not contain THC
- Due to the relatively recent nature of CBD use for medicinal purposes (as a supplement at least), there are a distinct lack of studies when it comes to potential drug interactions between CBD and prescription medication like Prozac (fluoxetine). However, based on what we known about the metabolism and pharmacokinetic profile of Prozac and CBD, we can discern some possible interactions, which are discussed below.
How CBD Can Interact With Drugs
The two main constituents of marijuana, THC and CBD, are mainly metabolized by the cytochrome P450 system, the major enzymes involved in drug metabolism. Drug interactions often occur when a drug inhibits or induces one of these metabolizing enzymes.
When A CYP enzyme is inhibited, drug concentrations can increase, due reduced metabolism. For example:
- The antiretroviral drug ritonavir can inhibit CYP2D6, which is the enzyme that metabolizes Prozac. Taking ritonavir with Prozac can significantly increase Prozac levels, increasing the risk of side effects.
Conversely, there are also drugs that induce CYP enzymes. If A CYP enzyme is induced, metabolism speeds up, potentially reducing drug concentrations.
Numerous studies have shown that CBD can inhibit:
It is important to note that many of the studies that show CYP enzyme inhibition were only conducted in vitro, or in a lab/non-biological setting. There aren't many studies that have been conducted in humans. So while there may be an indication of a potential drug interaction based on enzyme inhibition, until studies are done with specific drugs like Prozac, much is unknown.
In fact, there have been studies that postulate that while CBD does inhibit certain metabolizing enzymes, the extent of inhibition is not significant and the concentrations of CBD needed to affect these metabolizing enzymes in humans far exceeds what is possible with usual dosing.
One of the only interactions that is fairly definitive in regard to CBD is with drugs metabolized by CYP2C19. The prescribing information for Epidiolex, the prescription CBD product, states the following regarding use of CBD with drugs metabolized by CYP2C19:
"In vivo data show that coadministration of EPIDIOLEX increases plasma concentrations of drugs that are metabolized by (i.e., are substrates of) CYP2C19 (e.g., diazepam) and may increase the risk of adverse reactions with these substrates [see Clinical Pharmacology (12.3)]. Consider a reduction in dosage of sensitive CYP2C19 substrates, as clinically appropriate, when coadministered with EPIDIOLEX."
Prozac- CBD (Cannibidiol) Interaction
- CYP2C9 (not CYP2C19)
- CYP2D6
As discussed above, certain studies indicate that CBD can inhibit the metabolizing enzymes listed above. Therefore, the use of CBD and Prozac together could theoretically increase Prozac levels, due to decreased metabolism. This could potentially increase the risk for adverse effects, such as:
- Nausea
- Diarrhea
- Headache
- Serotonin syndrome (rare)
However, there is no specific data on an interaction with Prozac and CBD. It is more a theoretical interaction, predicted based on what we know of the metabolism of both drugs.
Summary
- CBD (cannibidiol) is a non-euphoric constituent of cannabis plant, used for a variety of indications including pain and anxiety.
- There is a definitive lack of data available regarding whether or not CBD interacts Prozac (fluoxetine).
- There is however, a theoretical interaction between CBD and Prozac based on how CBD can inhibit CYP metabolizing enzymes which are responsible for Prozac metabolism.
