Drug interactions
Doxazosin + Tamsulosin
Severity: Major
Doxazosin and Tamsulosin: 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
Both are alpha-1 blockers, so combining them adds no clear benefit and increases the risk of hypotension, dizziness and syncope. First-dose and postural effects are of particular concern in older adults.
What this interaction means in plain words
Doxazosin and Tamsulosin 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.
Doxazosin belongs to Genitourinary; Tamsulosin belongs to Genitourinary.
Why it happens
Additive alpha-1 adrenergic receptor blockade causing vasodilation.
What to do
Avoid using two alpha-blockers together and use a single agent at an optimized dose. If switching, stop one before starting the other and monitor standing blood pressure.
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 Doxazosin
- Alfuzosin + Doxazosin Major
- Amifostine + Doxazosin Major
- Avanafil + Doxazosin Major
- Doxazosin + Dutasteride-tamsulosin Major
- Doxazosin + Phentolamine Major
- Doxazosin + Prazosin Major
Other interactions of Tamsulosin
- Alfuzosin + Tamsulosin Major
- Avanafil + Tamsulosin Major
- Ceritinib + Tamsulosin Major
- Clarithromycin + Tamsulosin Major
- Cobicistat + Tamsulosin Major
- Idelalisib + Tamsulosin Major
Frequently asked questions
Can I take Doxazosin with Tamsulosin?
MediHelp rates the interaction as major. Doxazosin and Tamsulosin 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 are alpha-1 blockers, so combining them adds no clear benefit and increases the risk of hypotension, dizziness and syncope. First-dose and postural effects are of particular concern in older adults.
How serious is the interaction between Doxazosin and Tamsulosin?
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 use a single agent at an optimized dose. If switching, stop one before starting the other and monitor standing blood pressure.
What other medicines interact with Doxazosin?
MediHelp also lists interactions of Doxazosin with, for example, Alfuzosin, Amifostine, Avanafil. The full list is on the Doxazosin page.
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