Cannabis and prescription medications

Understanding Cannabis and Prescription Medication Interactions

Hello, fellow cannabis learners! I hope you had a great weekend—I enjoyed the warmer weather and spending some time in the garden. With everything happening in the world, it’s important to find moments of positivity. For me that is spending time in the garden as well as learning about medicinal cannabis. Today, let’s dive into an essential topic: cannabis and prescription medication interactions.

Cannabis can be a powerful tool for wellness, but just like any other medicine, it’s crucial to understand how it interacts with other medications. Education on potential interactions helps ensure safe and effective use of medicinal cannabis.

Why Do Medication Interactions Matter?

Medications take a complex journey through the body. They must be broken down in the digestive system, absorbed into the bloodstream, and interact with the right receptors to have their intended effects. Since cannabis interacts with the body's endocannabinoid system, which spans throughout the body, it can influence how other medications work.

If two or more medications are metabolized through the same pathway, they may compete, affecting how well they function. This could lead to one medication working too strongly, not strongly enough, or having unintended effects.

How Is Cannabis Metabolized?

When cannabis is ingested (such as in edibles or capsules), it is processed in the CYP450 enzyme system, primarily in the liver. This system is responsible for metabolizing about 90% of conventional medications in three phases:

• Phase I: Breaks down the medication (through oxidation, reduction, and hydrolysis).

• Phase II: Further processes active compounds so they can be excreted.

• Phase III: Completes the breakdown of remaining compounds for elimination (less common).

What Happens When Cannabis and Prescription Medications Compete?

If two medications rely on the same CYP450 pathway, they can interfere with each other. For example, cannabis and fluoxetine (Prozac) may compete at the same receptor sites. If cannabis gets there first, fluoxetine may not work as expected. On the flip side, fluoxetine could amplify THC’s effects, leading to a much stronger reaction than anticipated.

Key Medication Interactions to Be Aware Of

• CYP3A4 inhibitors (like ketoconazole) can double THC and CBD concentrations, intensifying their effects.

• CBD inhibits CYP2C19, increasing active metabolites of medications like clobazam, warfarin, and tacrolimus—potentially threefold.

• Smoking cannabis can increase how fast CYP1A2-metabolized medications (like theophylline and olanzapine) are cleared from the body. This is more pronounced in frequent users.

• CYP3A4 and CYP2C9 inhibitors can enhance cannabinoid effects, making THC or CBD feel stronger.

Examples of Medications Affected:

• CYP3A4-metabolized drugs: Amiodarone, Diltiazem, Fluconazole

• CYP2C9-metabolized drugs: Amlodipine, Atorvastatin, Clopidogrel

Final Thoughts

Understanding cannabis-medication interactions is essential for safe and effective use. If you're using cannabis alongside prescription medications, be mindful of potential effects and consult a healthcare provider when needed.

Want to dive deeper into cannabis education? Check out my book, Medical Cannabis: Preparing for Oklahoma’s Dispensaries for more in-depth insights! If you have any questions or need guidance, feel free to reach out—I’m always happy to help!

References

1. Smith RT, Gruber SA. Contemplating cannabis? The complex relationship between cannabinoids and hepatic metabolism resulting in the potential for drug-drug interactions. Front Psychiatry. 2023 Jan 10; 13:1055481. doi:10.3389/fpsyt.2022. 1055481. PMID: 36704740. PMCID: PMC9871609