Drug interactions
Phentolamine + Terazosin
Severity: Major
Phentolamine and Terazosin: 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-adrenergic antagonists, so using them together produces additive vasodilation and can cause marked hypotension, dizziness and reflex tachycardia. The combination offers no therapeutic advantage in most settings.
What this interaction means in plain words
Phentolamine and Terazosin 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; Terazosin belongs to Genitourinary.
Why it happens
Additive alpha-adrenergic receptor blockade causing vasodilation.
What to do
Avoid concurrent use unless specifically intended, such as in pheochromocytoma management. If combined, monitor blood pressure and heart rate closely and reduce 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 Terazosin
- Alfuzosin + Terazosin Major
- Amifostine + Terazosin Major
- Avanafil + Terazosin Major
- Doxazosin + Terazosin Major
- Dutasteride-tamsulosin + Terazosin Major
- Lofexidine + Terazosin Major
Other interactions of Phentolamine
Frequently asked questions
Can I take Phentolamine with Terazosin?
MediHelp rates the interaction as major. Phentolamine and Terazosin 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-adrenergic antagonists, so using them together produces additive vasodilation and can cause marked hypotension, dizziness and reflex tachycardia. The combination offers no therapeutic advantage in most settings.
How serious is the interaction between Phentolamine and Terazosin?
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 unless specifically intended, such as in pheochromocytoma management. If combined, monitor blood pressure and heart rate closely and reduce doses.
What other medicines interact with Terazosin?
MediHelp also lists interactions of Terazosin with, for example, Alfuzosin, Amifostine, Avanafil. The full list is on the Terazosin page.
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