Drug interactions
Fosamprenavir + Vardenafil
Severity: Major
Fosamprenavir and Vardenafil: major interaction.
Last updated Sources: US FDA label
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
Fosamprenavir, via amprenavir, inhibits CYP3A4 and may increase vardenafil exposure, raising the risk of hypotension, visual changes and prolonged erection.
What this interaction means in plain words
Fosamprenavir and Vardenafil can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Inhibition of CYP3A4-mediated vardenafil metabolism by amprenavir.
What to do
Use the reduced vardenafil dose and long interval recommended for HIV protease inhibitors, and monitor blood pressure and adverse effects.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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 Fosamprenavir with Vardenafil?
MediHelp rates the interaction as major. Fosamprenavir and Vardenafil can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Fosamprenavir, via amprenavir, inhibits CYP3A4 and may increase vardenafil exposure, raising the risk of hypotension, visual changes and prolonged erection.
How serious is the interaction between Fosamprenavir and Vardenafil?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the reduced vardenafil dose and long interval recommended for HIV protease inhibitors, and monitor blood pressure and adverse effects.
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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