Drug interactions
St john's wort + Vardenafil
Severity: Moderate
St john's wort and Vardenafil: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
St John's wort induces CYP3A4 and P-glycoprotein and may lower vardenafil exposure. The expected consequence is reduced efficacy.
What this interaction means in plain words
St john's wort and Vardenafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Induction of CYP3A4 by St John's wort lowers vardenafil levels.
What to do
Advise patients to stop St John's wort or expect a reduced response. Recheck vardenafil effect after stopping, since levels will rise as the induction wanes.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Vardenafil
- Amyl nitrite + Vardenafil Contraindicated
- Glyceryl trinitrate pr + Vardenafil Contraindicated
- Isosorbide dinitrate + Vardenafil Contraindicated
- Isosorbide mononitrate + Vardenafil Contraindicated
- Nicorandil + Vardenafil Contraindicated
- Nitroglycerin po + Vardenafil Contraindicated
Frequently asked questions
Can I take St john's wort with Vardenafil?
MediHelp rates the interaction as moderate. St john's wort and Vardenafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. St John's wort induces CYP3A4 and P-glycoprotein and may lower vardenafil exposure. The expected consequence is reduced efficacy.
How serious is the interaction between St john's wort and Vardenafil?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to stop St John's wort or expect a reduced response. Recheck vardenafil effect after stopping, since levels will rise as the induction wanes.
What other medicines interact with Vardenafil?
MediHelp also lists interactions of Vardenafil with, for example, Amyl nitrite, Glyceryl trinitrate pr, Isosorbide dinitrate. The full list is on the Vardenafil page.
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