Drug interactions
Prazosin + Silodosin
Severity: Major
Prazosin and Silodosin: 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
Prazosin and silodosin are both alpha-1 adrenergic blockers, so combining them duplicates therapy. This increases the risk of significant hypotension, orthostatic dizziness and syncope without a clear added benefit.
What this interaction means in plain words
Prazosin and Silodosin 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; Silodosin belongs to Genitourinary.
Why it happens
Additive alpha-1 adrenergic receptor blockade causing vasodilation.
What to do
Avoid using two alpha-blockers together and choose one agent. If the combination cannot be avoided, monitor orthostatic blood pressure closely.
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 Silodosin
- Atazanavir + Silodosin Contraindicated
- Conivaptan + Silodosin Contraindicated
- Darunavir + Silodosin Contraindicated
- Fosamprenavir + Silodosin Contraindicated
- Indinavir + Silodosin Contraindicated
- Itraconazole + Silodosin 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 Silodosin?
MediHelp rates the interaction as major. Prazosin and Silodosin 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 and silodosin are both alpha-1 adrenergic blockers, so combining them duplicates therapy. This increases the risk of significant hypotension, orthostatic dizziness and syncope without a clear added benefit.
How serious is the interaction between Prazosin and Silodosin?
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 using two alpha-blockers together and choose one agent. If the combination cannot be avoided, monitor orthostatic blood pressure closely.
What other medicines interact with Silodosin?
MediHelp also lists interactions of Silodosin with, for example, Atazanavir, Conivaptan, Darunavir. The full list is on the Silodosin page.
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