Guarana - Flutamide Interaction
Herbal: Guarana
Also Known As: Paullinia cupana, Brazilian Cocoa, Cacao Brésilien, Guarana Seed Extract, Guaranine, Zoom
Drug: Flutamide
Brand names:
Eulexin, Euflex
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jun 22, 2025
Interaction Details
Flutamide is classified as belonging to the following category: Flutamide (Eulexin)
Theoretically, guarana might increase the levels and adverse effects of flutamide.
Guarana contains caffeine. In vitro evidence shows that caffeine can inhibit the metabolism of flutamide. However, this effect has not been reported in humans.
Interaction Rating
Likelihood of Occurrence
ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
References
- Shet, M. S., McPhaul, M., Fisher, C. W., Stallings, N. R., and Estabrook, R. W. Metabolism of the antiandrogenic drug (Flutamide) by human CYP1A2. Drug Metab Dispos. 1997;25(11):1298-1303.
Guarana Overview
Guarana (Paullinia cupana) is a plant native to the Amazon rainforest in South America. The seeds of the guarana plant are used in traditional medicine and as a dietary supplement.
Guarana is often marketed as a natural stimulant and is claimed to improve physical performance, increase energy and alertness, and reduce fatigue. It is sometimes added to energy drinks, weight loss supplements, and other products.
Guarana seeds typically contain around 3-6% caffeine, although some extracts may contain far more. Guarana, when used in dietary supplements, is often standardized for its caffeine and tannin content.
Flutamide Overview
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Flutamide is used together with a luteinizing hormone-releasing hormone agonist (LHRH; a type of hormonal injection such as leuprolide [Lupron, Eligard], goserelin [Zoladex], or triptorelin [Trelstar]) to treat certain types of prostate cancer. Flutamide is in a class of medications called nonsteroidal antiandrogens. It works by blocking the effects of androgen (a male hormone) to stop the growth and spread of cancer cells.
Guarana - More Interactions
Guarana interacts with 647 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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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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