St. John's Wort - Revatio (Sildenafil) Interaction
Herbal: St. John's Wort
Also Known As: Hypericum perforatum, Amber Touch-and-Heal, Barbe de Saint-Jean, Chasse-diable, Demon Chaser, Fuga Daemonum, Hardhay, Herbe Aux Mille Vertus, Hypereikon, Hyperici Herba, Hypericum, Millepertuis, Perforate St. John's Wort, Racecourse Weed, Rosin Rose, Saynt Johannes Wort
Drug: Sildenafil
Brand names:
Revatio
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jun 09, 2024
Interaction Details
Sildenafil is classified as belonging to the following category: Cytochrome P450 2C9 (Cyp2C9) Substrates
St. John's wort may increase the metabolism and reduce the levels of CYP2C9 substrates.
There is contradictory research about the effect of St. John's wort on CYP2C9. Some in vitro research shows that St. John's wort induces CYP2C9, but to a lesser extent than CYP3A4. St. John's wort also induces metabolism of the S-warfarin isomer, which is a CYP2C9 substrate. Other research shows that St. John's wort 300 mg three times daily for 21 days does not significantly affect the pharmacokinetics of a single 400 mg dose of ibuprofen, which is also a CYP2C9 substrate. Until more is known, use St. John's wort cautiously in patients who are taking CYP2C9 substrates.
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
- Henderson L, Yue QY, Bergquist C, et al. St John's wort (Hypericum perforatum): drug interactions and clinical outcomes. Br J Clin Pharmacol 2002;54:349-56..
- Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42..
- Komoroski BJ, Zhang S, Cai H, et al. Induction and inhibition of cytochromes P450 by the St. John's wort constituent hyperforin in human hepatocyte cultures. Drug Metab Dispos 2004;32:512-8.
- Jiang X, Williams KM, Liauw WS, et al. Effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol 2004;57:592-9.
- Bell EC, Ravis WR, Lloyd KB, Stokes TJ. Effects of St. John's wort supplementation on ibuprofen pharmacokinetics. Ann Pharmacother 2007;41:229-34.
Interaction Details
Sildenafil is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates
St. John's wort increases the metabolism and reduces the levels of CYP3A4 substrates.
St. John's wort induces CYP3A4 enzymes and increases metabolism of CYP3A4 substrates. Clinically significant interactions have been reported with St. John's wort products containing hyperforin 1 mg or more.
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
- Henderson L, Yue QY, Bergquist C, et al. St John's wort (Hypericum perforatum): drug interactions and clinical outcomes. Br J Clin Pharmacol 2002;54:349-56..
- Markowitz JS, Donovan JL, DeVane CL, et al. Effect of St. John's wort on drug metabolism by induction of cytochrome P450 3A4 enzyme. JAMA 2003;290:1500-4..
- Gurley BJ, Gardner SF, Hubbard MA, et al. Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002;72:276-87..
- Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42..
- Komoroski BJ, Zhang S, Cai H, et al. Induction and inhibition of cytochromes P450 by the St. John's wort constituent hyperforin in human hepatocyte cultures. Drug Metab Dispos 2004;32:512-8.
- Smith M, Lin KM, and Zheng YP. PIII-89 an open trial of nifedipine-herb interactions: Nifedipine with St. John's wort, ginseng or ginkgo biloba. Clin Pharm Ther 2001;69:P86.
- Kawaguchi, A., Ohmori, M., Tsuruoka, S., Nishiki, K., Harada, K., Miyamori, I., Yano, R., Nakamura, T., Masada, M., and Fujimura, A. Drug interaction between St John's Wort and quazepam. Br.J.Clin Pharmacol. 2004;58(4):403-410.
- Dresser, G. K., Schwarz, U. I., Wilkinson, G. R., and Kim, R. B. Coordinate induction of both cytochrome P4503A and MDR1 by St John's wort in healthy subjects. Clin Pharmacol Ther 2003;73(1):41-50.
- Patel, J., Buddha, B., Dey, S., Pal, D., and Mitra, A. K. In vitro interaction of the HIV protease inhibitor ritonavir with herbal constituents: changes in P-gp and CYP3A4 activity. Am.J.Ther. 2004;11(4):262-277.
- Izzo, A. A. and Ernst, E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs 2009;69(13):1777-1798.
- Chrubasik-Hausmann S, Vlachojannis J, McLachlan AJ. Understanding drug interactions with St John's wort (Hypericum perforatum L.): impact of hyperforin content. J Pharm Pharmacol. 2018.
St. John's Wort Overview
Sildenafil Overview
-
Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Revatio) is used to improve the ability to exercise in adults and children 1 year of age and older with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the lungs, causing shortness of breath, dizziness, and tiredness). Sildenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily.
-
If you are taking sildenafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire. Sildenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV).
St. John's Wort - More Interactions
St. John's Wort interacts with 1113 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. |
Return to the main herbal interaction checker page
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.