Saw Palmetto - Faslodex (Fulvestrant) Interaction
Herbal: Saw Palmetto
Also Known As: Serenoa repens, American Dwarf Palm Tree, Baies du Palmier Scie, Cabbage Palm, Chou Palmiste, Ju-Zhong, Palmier Nain, Palmier Scie, Sabal, Sabal Fructus, Saw Palmetto Berry
Drug: Fulvestrant
Brand names:
Faslodex
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 25, 2025
Interaction Details
There were no interactions found between Fulvestrant and Saw Palmetto. This does not mean the potential for an interaction does not exist, however. There is often a lack of studies and data surrounding traditional medicine, especially concerning drug interactions, so it is important to always consult your provider before making any changes to your medication regimen.
Pharmacist Analysis
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On the whole, saw palmetto has very few reported drug interactions due to its lack of effects on liver metabolizing enzymes (e.g., CYP P450 enzymes).
There have been some reports of minor interactions with anticoagulants, estrogens, and contraceptives due to saw palmetto's purported effects on blood clotting and various hormones in the body. However, these interactions have generally only been seen in lab studies and for most individuals, are not considered clinically significant.
As always, however, be sure to talk to your doctor before starting any new medications or supplements so you can be appropriately monitored.
Comprehensive analysis does not indicate a significant interaction.
- Dr. Brian Staiger, PharmDSaw Palmetto Overview
Saw palmetto (Serenoa repens) is a plant native to the southeastern United States and a member of the Arecaceae family. It is a small, palm-like tree with fan-shaped leaves that produces small, white flowers. The fruit of the plant is a small, dark purple berry, which is what is used in dietary supplements.
In traditional medicine, saw palmetto has been used to treat a variety of health conditions, including prostate problems (such as BPH [benign prostatic hyperplasia]) and urinary tract disorders. It is also claimed to have anti-inflammatory and antioxidant properties and to improve hair growth.
Fulvestrant Overview
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Fulvestrant injection is used alone or in combination with ribociclib (Kisqali®) to treat a certain type of hormone receptor positive, advanced breast cancer (breast cancer that depends on hormones such as estrogen to grow) or breast cancer has spread to other parts of the body in women who have experienced menopause (change of life; end of monthly menstrual periods) and have not previously been treated with an anti-estrogen medication such as tamoxifen (Nolvadex). Fulvestrant injection is also used alone or in combination with ribociclib (Kisqali®) to treat hormone receptor positive, advanced breast cancer or breast cancer that has spread to other parts of the body in women who have experienced menopause and whose breast cancer has worsened after they were treated with an anti-estrogen medication such as tamoxifen. Fulvestrant injection is also used in combination with palbociclib (Ibrance®) or abemaciclib (Verzenio®) to treat hormone receptor positive, advanced breast cancer in women whose breast cancer has spread to other parts of the body and has worsened after they were treated with anti-estrogen medication such as tamoxifen. Fulvestrant is in a class of medications called estrogen receptor antagonists. It works by blocking the action of estrogen on cancer cells. This can slow or stop the growth of some breast tumors that need estrogen to grow.
Saw Palmetto - More Interactions
Saw Palmetto interacts with 173 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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