Drug interactions
Phenoxybenzamine + Terazosin
Severity: Moderate
Phenoxybenzamine and Terazosin: moderate 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 drugs block alpha-adrenergic receptors, so combining them may cause excessive vasodilation. Marked hypotension, syncope and reflex tachycardia can occur.
What this interaction means in plain words
Phenoxybenzamine and Terazosin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive alpha-1 adrenergic blockade, with phenoxybenzamine acting as an irreversible non-selective blocker.
What to do
Avoid duplicate alpha-blockade unless clinically intended; if combined, titrate slowly and monitor supine and standing blood pressure.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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
Frequently asked questions
Can I take Phenoxybenzamine with Terazosin?
MediHelp rates the interaction as moderate. Phenoxybenzamine and Terazosin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs block alpha-adrenergic receptors, so combining them may cause excessive vasodilation. Marked hypotension, syncope and reflex tachycardia can occur.
How serious is the interaction between Phenoxybenzamine and Terazosin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid duplicate alpha-blockade unless clinically intended; if combined, titrate slowly and monitor supine and standing blood pressure.
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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