Drug interactions
Avanafil + Phenoxybenzamine
Severity: Major
Avanafil and Phenoxybenzamine: major interaction.
Last updated Sources: US FDA label
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
Both drugs lower blood pressure, and combining a PDE5 inhibitor with an alpha-blocker can cause symptomatic hypotension, dizziness or syncope. The risk is greatest at treatment initiation or after dose increases.
What this interaction means in plain words
Avanafil and Phenoxybenzamine 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
Additive vasodilation from PDE5 inhibition and irreversible alpha-adrenergic blockade.
What to do
Ensure the patient is stable on the alpha-blocker before starting avanafil at the lowest dose. Monitor blood pressure and counsel on orthostatic symptoms.
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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References
Other interactions of Avanafil
- Amyl nitrite + Avanafil Contraindicated
- Atazanavir + Avanafil Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Avanafil + Conivaptan Contraindicated
- Avanafil + Darunavir Contraindicated
- Avanafil + Fosamprenavir Contraindicated
Frequently asked questions
Can I take Avanafil with Phenoxybenzamine?
MediHelp rates the interaction as major. Avanafil and Phenoxybenzamine 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. Both drugs lower blood pressure, and combining a PDE5 inhibitor with an alpha-blocker can cause symptomatic hypotension, dizziness or syncope. The risk is greatest at treatment initiation or after dose increases.
How serious is the interaction between Avanafil and Phenoxybenzamine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Ensure the patient is stable on the alpha-blocker before starting avanafil at the lowest dose. Monitor blood pressure and counsel on orthostatic symptoms.
What other medicines interact with Avanafil?
MediHelp also lists interactions of Avanafil with, for example, Amyl nitrite, Atazanavir, Clarithromycin. The full list is on the Avanafil page.
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