Drug interactions
Saquinavir + Vardenafil
Severity: Major
Saquinavir and Vardenafil: major 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
Saquinavir, usually given with ritonavir, strongly inhibits CYP3A4 and can greatly increase vardenafil exposure. Hypotension, syncope and QT prolongation are of concern, and saquinavir itself prolongs QT.
What this interaction means in plain words
Saquinavir 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
CYP3A4 inhibition by saquinavir plus additive QT prolongation.
What to do
Limit vardenafil to 2.5 mg in 24 hours (less often if ritonavir-boosted) and monitor blood pressure and ECG.
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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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 Saquinavir with Vardenafil?
MediHelp rates the interaction as major. Saquinavir 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. Saquinavir, usually given with ritonavir, strongly inhibits CYP3A4 and can greatly increase vardenafil exposure. Hypotension, syncope and QT prolongation are of concern, and saquinavir itself prolongs QT.
How serious is the interaction between Saquinavir 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: Limit vardenafil to 2.5 mg in 24 hours (less often if ritonavir-boosted) and monitor blood pressure and ECG.
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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