Drug interactions
Conivaptan + Tadalafil
Severity: Major
Conivaptan 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
Conivaptan is a strong CYP3A4 inhibitor and can raise tadalafil exposure, increasing risks of hypotension, headache, and priapism. Tadalafil labeling advises dose limits with strong CYP3A4 inhibitors.
What this interaction means in plain words
Conivaptan 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.
Why it happens
Inhibition of CYP3A4 by conivaptan reduces tadalafil clearance.
What to do
Limit tadalafil for erectile dysfunction to 2.5 mg daily or 10 mg no more often than every 72 hours, and avoid use for pulmonary hypertension. Monitor blood pressure.
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
Frequently asked questions
Can I take Conivaptan with Tadalafil?
MediHelp rates the interaction as major. Conivaptan 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. Conivaptan is a strong CYP3A4 inhibitor and can raise tadalafil exposure, increasing risks of hypotension, headache, and priapism. Tadalafil labeling advises dose limits with strong CYP3A4 inhibitors.
How serious is the interaction between Conivaptan 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: Limit tadalafil for erectile dysfunction to 2.5 mg daily or 10 mg no more often than every 72 hours, and avoid use for pulmonary hypertension. Monitor blood pressure.
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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