Cannabis is a plant with enormous health potential. We know that the cannabinoids that give cannabis its amazing effects are very safe. We also know that one of those cannabinoids, CBD (Cannabidiol), has the potential to reduce the effectiveness of certain medications. One of those medications is contraceptives.

When you take birth control to prevent pregnancy, you put your trust in their consistent effectiveness. Knowing how CBD can possibly affect your birth control can help you to continue to prevent an unwanted pregnancy.

The Geekery Behind the Caution

CBD is a safe, non-impairing component of cannabis with numerous health benefits. Many patients take daily CBD in edible oils or through dry bud vaporization.

So why the concern? CBD, especially in higher doses, has the potential to interact with certain medications by inhibiting (slowing down) the activity of a liver enzyme called cytochrome P450.

Wait a minute… Cyto-P-what-the-what?

CP450 is responsible for helping our bodies to process more than 60 percent of medications. In fact, it is more potent in blocking and slowing down your body’s use of these medications than grapefruit. Have a look at the print-out that came from your pharmacy — does it advise you to avoid grapefruit while on this medication? If so, then CBD probably interacts, too.

An interesting aside is that this is the reason why using a 1:1 Balanced CBD/THC oil or strain causes less of a high than using straight THC at the same level. The CBD counteracts much of that psychoactive effect.

It is possible that whole plant cannabis, with its entourage effect, interacts differently than the isolated CBD that is administered in most research settings. Certainly, you will want to avoid currently non-approved (and therefore non-legal, and also not available from Canada’s Licensed Producers) high CBD isolates and distillates.

What does this mean for my birth control?

Enzyme inhibitors (for example CBD), can possibly increase breakthrough bleeding and potentially decrease estrogen-based contraceptive effectiveness, which may lead to increased risk of pregnancy. Studies are currently being done to determine if they may also increase the risk of side effects like blood clots and breast cancer.

The active hormones in your birth control can also make a difference. Estrogen-containing oral contraceptives, patches, injections, and rings are at higher risk of not working properly in the presence of CBD than non-estrogen forms. Progesterone-only contraceptives may be a more dependable option if you are using CBD, especially via ingestible oils. Talk to your doctor about your options, and consider using additional methods of birth control such as condoms if you are relying on an estrogen form and using CBD oil daily. We don’t yet know at what level CBD affects estrogen and currently can only recommend caution and awareness.

We also know now that combining certain things with CBD and birth control can potentially interact even further. Cigarette smoking, chronic alcohol use, and St. John’s Wort are three big players and should be avoided while on birth control, and especially when using CBD.

Written by Shawna Zylenko, RN, Natural Health Services. Shawna work out of our Edmonton Clinic and is a member of the American Cannabis Nurses Association (ACNA) and has received her Cannabis Nursing Certification (2016) through TMCI/ACNA.

For further insight into all things Cannabis, don’t forget to tune in to The Cannabis Show, and make sure to subscribe as there is a new episode every Wednesday.

Sources:

https://www.ncbi.nlm.nih.gov/pubmed/21704641  Identification of cytochrome P450 enzymes responsible for metabolism of cannabidiol by human liver microsomes  Life Sci. 2011 Aug 1;89(5-6):165-70. 2011.

https://www.ncbi.nlm.nih.gov/pubmed/26651971   Cannabinoids and Cytochrome P450 Interactions. Curr Drug Metab. 2016;17(3):206-26.

http://www.medicinalgenomics.com/wp-content/uploads/2013/11/Potent-inhibition-of-CYP3A-with-CBD.pdf  

https://www.fda.gov/downloads/Drugs/NewsEvents/UCM473688.pdf  Design and Interpretation of Oral Contraceptive Drug-Drug Interaction Studies.

http://nursinglink.monster.com/training/articles/320-clinically-significant-drug-interaction-with-the-cytochrome-p450-enzyme-system

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