Drug interactions
Indinavir + Sildenafil
Severity: Major
Indinavir and Sildenafil: 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
Indinavir inhibits CYP3A4 and raises sildenafil exposure, increasing the risk of hypotension, syncope, visual disturbances and prolonged erection.
What this interaction means in plain words
Indinavir and Sildenafil 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 sildenafil metabolism by indinavir.
What to do
For erectile dysfunction, use a starting dose of 25 mg and, with ritonavir-boosted indinavir, no more than 25 mg in 48 hours. Monitor for hypotension and priapism.
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 Sildenafil
- Amyl nitrite + Sildenafil Contraindicated
- Atazanavir + Sildenafil Contraindicated
- Cobicistat + Sildenafil Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Sildenafil Contraindicated
- Glyceryl trinitrate pr + Sildenafil Contraindicated
- Isosorbide dinitrate + Sildenafil Contraindicated
Frequently asked questions
Can I take Indinavir with Sildenafil?
MediHelp rates the interaction as major. Indinavir and Sildenafil 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. Indinavir inhibits CYP3A4 and raises sildenafil exposure, increasing the risk of hypotension, syncope, visual disturbances and prolonged erection.
How serious is the interaction between Indinavir and Sildenafil?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: For erectile dysfunction, use a starting dose of 25 mg and, with ritonavir-boosted indinavir, no more than 25 mg in 48 hours. Monitor for hypotension and priapism.
What other medicines interact with Sildenafil?
MediHelp also lists interactions of Sildenafil with, for example, Amyl nitrite, Atazanavir, Cobicistat. The full list is on the Sildenafil page.
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