Drug interactions
Ritonavir + Tadalafil
Severity: Major
Ritonavir and Tadalafil: 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
Ritonavir is a strong CYP3A4 inhibitor and markedly increases tadalafil exposure. This can cause severe hypotension, syncope, visual changes and prolonged erection.
What this interaction means in plain words
Ritonavir and Tadalafil 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.
Ritonavir belongs to Anti Virals; Tadalafil belongs to Genitourinary.
Why it happens
Ritonavir strongly inhibits CYP3A4, greatly reducing tadalafil clearance.
What to do
For erectile dysfunction, use the labeled reduced maximum doses and monitor blood pressure and priapism. For pulmonary hypertension, follow labeling on stopping tadalafil before ritonavir and restarting at a low dose.
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 Tadalafil
- Amyl nitrite + Tadalafil Contraindicated
- Isosorbide dinitrate + Tadalafil Contraindicated
- Isosorbide mononitrate + Tadalafil Contraindicated
- Nitroglycerin po + Tadalafil Contraindicated
- Nitroglycerin rectal + Tadalafil Contraindicated
- Nitroglycerin sublingual + Tadalafil Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Tadalafil?
MediHelp rates the interaction as major. Ritonavir and Tadalafil 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. Ritonavir is a strong CYP3A4 inhibitor and markedly increases tadalafil exposure. This can cause severe hypotension, syncope, visual changes and prolonged erection.
How serious is the interaction between Ritonavir and Tadalafil?
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 the labeled reduced maximum doses and monitor blood pressure and priapism. For pulmonary hypertension, follow labeling on stopping tadalafil before ritonavir and restarting at a low dose.
What other medicines interact with Tadalafil?
MediHelp also lists interactions of Tadalafil with, for example, Amyl nitrite, Isosorbide dinitrate, Isosorbide mononitrate. The full list is on the Tadalafil page.
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