Drug interactions
Idelalisib + Tadalafil
Severity: Major
Idelalisib 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
Idelalisib is a strong CYP3A inhibitor and can substantially increase tadalafil levels. This increases the risk of severe hypotension, syncope, visual disturbance and priapism.
What this interaction means in plain words
Idelalisib 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.
Idelalisib belongs to Oncology; Tadalafil belongs to Genitourinary.
Why it happens
Idelalisib strongly inhibits CYP3A4, decreasing tadalafil metabolism.
What to do
Avoid for pulmonary hypertension use; for erectile dysfunction use reduced tadalafil dosing per labeling and monitor blood pressure. Consider alternative therapy where feasible.
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 Idelalisib
- Alfuzosin + Idelalisib Contraindicated
- Cisapride + Idelalisib Contraindicated
- Dihydroergotamine + Idelalisib Contraindicated
- Dronedarone + Idelalisib Contraindicated
- Eletriptan + Idelalisib Contraindicated
- Eplerenone + Idelalisib Contraindicated
Frequently asked questions
Can I take Idelalisib with Tadalafil?
MediHelp rates the interaction as major. Idelalisib 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. Idelalisib is a strong CYP3A inhibitor and can substantially increase tadalafil levels. This increases the risk of severe hypotension, syncope, visual disturbance and priapism.
How serious is the interaction between Idelalisib 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: Avoid for pulmonary hypertension use; for erectile dysfunction use reduced tadalafil dosing per labeling and monitor blood pressure. Consider alternative therapy where feasible.
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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