Guarana - Ethinyl Estradiol, Norethindrone, Ferrous Fumarate Interaction
Herbal: Guarana
Also Known As: Paullinia cupana, Brazilian Cocoa, Cacao Brésilien, Guarana Seed Extract, Guaranine, Zoom
Drug: Ethinyl Estradiol, Norethindrone, Ferrous Fumarate
Brand names:
Estrostep Fe, Loestrin Fe, Microgestin FE, Junel Fe 1.5/30, Loestrin Fe 1.5/30, Microgestin Fe 1.5/30, Loestrin-24 FE, Femcon FE, Loestrin Fe 1/20
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Ethinyl Estradiol, Norethindrone, Ferrous Fumarate is classified as belonging to the following category: Cytochrome P450 1A2 (Cyp1A2) Inhibitors
Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Caffeine is metabolized by the CYP1A2 enzyme. Theoretically, drugs that inhibit CYP1A2 may decrease the rate of caffeine clearance and increase caffeine levels.
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
- Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63.
- Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53.
Interaction Details
Ethinyl Estradiol, Norethindrone, Ferrous Fumarate is classified as belonging to the following category: Estrogens
Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Estrogen inhibits caffeine metabolism.
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
- Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40.
Interaction Details
Ethinyl Estradiol, Norethindrone, Ferrous Fumarate is classified as belonging to the following category: Contraceptive Drugs
Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in guarana.
Guarana contains caffeine. Oral contraceptives decrease the rate of caffeine clearance by 40% to 65%.
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
- Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40.
- Abernethy DR, Todd EL. Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives. Eur J Clin Pharmacol 1985;28:425-8.
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.
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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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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