Drug interactions
Phenoxybenzamine + Tadalafil
Severity: Moderate
Phenoxybenzamine and Tadalafil: moderate 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
Phenoxybenzamine is a long-acting alpha-blocker and tadalafil is a vasodilator, so together they can cause additive hypotension. Orthostatic dizziness and syncope are the main concerns.
What this interaction means in plain words
Phenoxybenzamine and Tadalafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive vasodilation from irreversible alpha-adrenergic blockade and PDE5 inhibition.
What to do
Start tadalafil at the lowest dose and monitor blood pressure and orthostatic symptoms. Advise patients to rise slowly and report dizziness.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Phenoxybenzamine with Tadalafil?
MediHelp rates the interaction as moderate. Phenoxybenzamine and Tadalafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenoxybenzamine is a long-acting alpha-blocker and tadalafil is a vasodilator, so together they can cause additive hypotension. Orthostatic dizziness and syncope are the main concerns.
How serious is the interaction between Phenoxybenzamine and Tadalafil?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start tadalafil at the lowest dose and monitor blood pressure and orthostatic symptoms. Advise patients to rise slowly and report dizziness.
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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