Calamus - Femara (Letrozole) Interaction
Herbal: Calamus
Also Known As: Acorus calamus, Acore Calame, Acore Odorant, Acore Olorant, Acore Roseau, Acorus Roseau, Aruna, Bach, Bajai, Baje, Belle-Angélique, Bhutanashini, Cálamo, Calamo Aromatic, Calamus Root, Cinnamon Sedge, Flag Root, Flagroot, Gladdon, Golomi, Grass-Leaf Sweetflag, Grass Myrtle, Ka
Drug: Letrozole
Brand names:
Femara
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jul 22, 2023
Interaction Details
Letrozole is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates
In vitro research suggests that calamus inhibits cytochrome P450 3A4 (CYP3A4). Theoretically, use of calamus with drugs metabolized by CYP3A4 might increase drug levels and potentially increase the risk of adverse effects.
Some drugs metabolized by CYP3A4 include lovastatin (Mevacor), clarithromycin (Biaxin), indinavir (Crixivan), sildenafil (Viagra), triazolam (Halcion), and numerous others.
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
- Pandit S, Mukherjee PK, Ponnusankar S, Venkatesh M, Srikanth N. Metabolism mediated interaction of a-asarone and Acorus calamus with CYP3A4 and CYP2D6. Fitoterapia 2011;82(3):369-74.
Calamus Overview
Calamus is a grass-like plant commonly mostly commonly found in Eastern Europe in swamps or along the banks of waterways. Calamus has traditionally been used in both Ayurdevic and Chinese medicine for a number of ailments, including digestive disorders including colic, ulcers, gastritis, flatulence, diarrhea, intestinal infections, dyspepsia, and anorexia. It is also used to induce vomiting, induce sweating, improve memory and for the treatment of inflammatory disorders. The FDA does not allow calamus in food due research showing it has carcinogenic effects, likely due to the beta-asarone content, which can vary heavily depending on the species.
Letrozole Overview
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Letrozole is used treat early breast cancer in women who have experienced menopause (change of life; end of monthly menstrual periods) and who have had other treatments, such as radiation or surgery to remove the tumor. It is also used to treat early breast cancer in women who have experienced menopause and who have already been treated with a medication called tamoxifen (Nolvadex) for 5 years. Letrozole is also used in women who have experienced menopause as a first treatment of breast cancer that has spread within the breast or to other areas of the body or in women whose breast cancer has worsened while they were taking tamoxifen. Letrozole is in a class of medications called nonsteroidal aromatase inhibitors. It works by decreasing the amount of estrogen produced by the body. This can slow or stop the growth of some types of breast cancer cells that need estrogen to grow.
Calamus - More Interactions
Calamus interacts with 1071 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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