Drug interactions
Ketoconazole + Tadalafil
Severity: Major
Ketoconazole 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
Ketoconazole strongly inhibits CYP3A4 and increases tadalafil exposure, which can lead to marked hypotension, syncope, visual changes and priapism.
What this interaction means in plain words
Ketoconazole 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.
Ketoconazole belongs to Anti Fungals; Tadalafil belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4-mediated tadalafil metabolism.
What to do
For erectile dysfunction, cap tadalafil at 10 mg every 72 hours or 2.5 mg daily. Avoid in pulmonary hypertension and counsel on 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 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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Ketoconazole with Tadalafil?
MediHelp rates the interaction as major. Ketoconazole 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. Ketoconazole strongly inhibits CYP3A4 and increases tadalafil exposure, which can lead to marked hypotension, syncope, visual changes and priapism.
How serious is the interaction between Ketoconazole 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, cap tadalafil at 10 mg every 72 hours or 2.5 mg daily. Avoid in pulmonary hypertension and counsel on hypotension and priapism.
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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