Drug interactions
Prazosin + Vardenafil
Severity: Major
Prazosin and Vardenafil: 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 through vasodilation, and taken together they can cause symptomatic hypotension, dizziness or syncope. Alpha-blockers are generally not recommended with vardenafil, and the risk is greatest when treatment is started or doses are increased.
What this interaction means in plain words
Prazosin and Vardenafil 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.
Prazosin belongs to Genitourinary; Vardenafil belongs to Genitourinary.
Why it happens
Additive vasodilation from alpha-1 adrenergic blockade combined with PDE5 inhibition.
What to do
Avoid the combination where possible; if it is needed, ensure the patient is stable on the alpha-blocker and start vardenafil 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 Vardenafil
- Amyl nitrite + Vardenafil Contraindicated
- Glyceryl trinitrate pr + Vardenafil Contraindicated
- Isosorbide dinitrate + Vardenafil Contraindicated
- Isosorbide mononitrate + Vardenafil Contraindicated
- Nicorandil + Vardenafil Contraindicated
- Nitroglycerin po + Vardenafil Contraindicated
Other interactions of Prazosin
- Alfuzosin + Prazosin Major
- Amifostine + Prazosin Major
- Avanafil + Prazosin Major
- Doxazosin + Prazosin Major
- Dutasteride-tamsulosin + Prazosin Major
- Phenoxybenzamine + Prazosin Major
Frequently asked questions
Can I take Prazosin with Vardenafil?
MediHelp rates the interaction as major. Prazosin and Vardenafil 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 through vasodilation, and taken together they can cause symptomatic hypotension, dizziness or syncope. Alpha-blockers are generally not recommended with vardenafil, and the risk is greatest when treatment is started or doses are increased.
How serious is the interaction between Prazosin and Vardenafil?
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 the combination where possible; if it is needed, ensure the patient is stable on the alpha-blocker and start vardenafil at the lowest dose. Monitor blood pressure and counsel on orthostatic symptoms.
What other medicines interact with Vardenafil?
MediHelp also lists interactions of Vardenafil with, for example, Amyl nitrite, Glyceryl trinitrate pr, Isosorbide dinitrate. The full list is on the Vardenafil page.
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