Drug interactions
Phentolamine + Silodosin
Severity: Major
Phentolamine and Silodosin: 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
Phentolamine is a nonselective alpha-adrenergic blocker, and silodosin is an alpha-1A blocker, so using them together duplicates alpha blockade. This can cause marked hypotension, dizziness and syncope.
What this interaction means in plain words
Phentolamine 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.
Phentolamine belongs to Cardiovascular; Silodosin belongs to Genitourinary.
Why it happens
Additive alpha-adrenergic receptor antagonism causing vasodilation and hypotension.
What to do
Avoid concurrent use where possible. If it is necessary, monitor blood pressure closely and start with low doses.
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 Silodosin
- Atazanavir + Silodosin Contraindicated
- Conivaptan + Silodosin Contraindicated
- Darunavir + Silodosin Contraindicated
- Fosamprenavir + Silodosin Contraindicated
- Indinavir + Silodosin Contraindicated
- Itraconazole + Silodosin Contraindicated
Other interactions of Phentolamine
Frequently asked questions
Can I take Phentolamine with Silodosin?
MediHelp rates the interaction as major. Phentolamine 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. Phentolamine is a nonselective alpha-adrenergic blocker, and silodosin is an alpha-1A blocker, so using them together duplicates alpha blockade. This can cause marked hypotension, dizziness and syncope.
How serious is the interaction between Phentolamine 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 concurrent use where possible. If it is necessary, monitor blood pressure closely and start with low doses.
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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