Cannabis - Finasteride Interaction
Herbal: Cannabis
Also Known As: Cannabis sativa, Anashca, Banji, Bhang, Blunt, Bud, Cannabis, Charas, Dope, Esrar, Gaga, Ganga, Grass, Haschisch, Hash, Hashish, Herbe, Huo Ma Ren, Joint, Kif, Marie-Jeanne, Mariguana, Marihuana, Marijuana, Mary Jane, Pot, Weed, Devil's Lettuce
Drug: Finasteride
Brand names:
Propecia, Proscar
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jun 22, 2025
Interaction Details
Finasteride is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates
Theoretically, cannabis may increase the levels and adverse effects of CYP3A4 substrates.
In vitro research shows that cannabis can inhibit the activity of CYP3A4 enzymes, which might decrease the metabolism of CYP3A4 substrates. In vitro research also shows that cannabis extracts modestly inhibit the CYP3A4 metabolism of testosterone; extracts providing the specific cannabinoids CBD and cannabigerol (CBG) had stronger inhibitory effects than extracts containing THC and CBD.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Pellinen, P., Honkakoski, P., Stenback, F., Niemitz, M., Alhava, E., Pelkonen, O., Lang, M. A., and Pasanen, M. Cocaine N-demethylation and the metabolism-related hepatotoxicity can be prevented by cytochrome P450 3A inhibitors. Eur.J Pharmacol 1-3-1994;2
- Treyer A, Reinhardt JK, Eigenmann DE, Oufir M, Hamburger M. Phytochemical comparison of medicinal cannabis extracts and study of their CYP-mediated interactions with coumarinic oral anticoagulants. Med Cannabis Cannabinoids. 2023;6(1):21-31.
Cannabis Overview
Cannabis, also known as marijuana, is a plant that contains more than 100 compounds known as cannabinoids. Some of these compounds can have psychoactive effects when consumed, which is why cannabis is often used for recreational purposes. However, cannabis has also been used for medicinal purposes and specific compounds found in cannabis (e.g., THC, CBD, CBN) are thought to have different effects and work on different receptors in the body. The two main cannabinoids in cannabis that are used medicinally are tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the psychoactive compound in cannabis, while CBD is not psychoactive. Cannabidiol (CBD) is also found in the prescription drug Epidiolex and is used to treat certain types of seizures.
Finasteride Overview
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Finasteride (Proscar) is used alone or in combination with another medication (doxazosin [Cardura]) to treat benign prostatic hypertrophy (BPH, enlargement of the prostate gland). Finasteride is used to treat symptoms of BPH such as frequent and difficult urination and may reduce the chance of acute urinary retention (sudden inability to urinate). It also may decrease the chance that prostate surgery will be needed. Finasteride (Propecia) is also used to treat male pattern hair loss (gradual thinning of the hair on the scalp, leading to a receding hairline or balding on the top of the head in men.) Finasteride (Propecia) has not been shown to treat thinning hair at the temples and is not used to treat hair loss in women or children. Finasteride is in a class of medications called 5-alpha reductase inhibitors. Finasteride treats BPH by blocking the body's production of a male hormone that causes the prostate to enlarge. Finasteride treats male pattern hair loss by blocking the body's production of a male hormone in the scalp that stops hair growth.
Cannabis - More Interactions
Cannabis interacts with 1096 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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