Drug interactions
Phenoxybenzamine + Silodosin
Severity: Major
Phenoxybenzamine 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
Phenoxybenzamine is a long-acting irreversible alpha-blocker. Combining it with silodosin causes additive alpha blockade with a risk of severe orthostatic hypotension and syncope.
What this interaction means in plain words
Phenoxybenzamine 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.
Why it happens
Additive alpha-adrenoceptor antagonism, with irreversible blockade by phenoxybenzamine.
What to do
Avoid combining the two alpha-blockers where possible. If unavoidable, monitor supine and standing blood pressure closely and use the lowest effective 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
Frequently asked questions
Can I take Phenoxybenzamine with Silodosin?
MediHelp rates the interaction as major. Phenoxybenzamine 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. Phenoxybenzamine is a long-acting irreversible alpha-blocker. Combining it with silodosin causes additive alpha blockade with a risk of severe orthostatic hypotension and syncope.
How serious is the interaction between Phenoxybenzamine 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 combining the two alpha-blockers where possible. If unavoidable, monitor supine and standing blood pressure closely and use the lowest effective 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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