Drug interactions
Doxazosin + Penbutolol
Severity: Moderate
Doxazosin and Penbutolol: 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 lower blood pressure, so using them together can produce greater hypotension than either alone. Dizziness, orthostatic hypotension and syncope are most likely after the first dose of doxazosin or after a dose increase.
What this interaction means in plain words
Doxazosin and Penbutolol 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 pharmacodynamic antihypertensive effect from alpha-1 adrenergic blockade combined with beta-adrenergic blockade.
What to do
Start doxazosin at a low dose at bedtime and titrate slowly. Monitor standing and sitting blood pressure and warn the patient about postural dizziness.
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 Doxazosin
- Alfuzosin + Doxazosin Major
- Amifostine + Doxazosin Major
- Avanafil + Doxazosin Major
- Doxazosin + Dutasteride-tamsulosin Major
- Doxazosin + Phentolamine Major
- Doxazosin + Prazosin Major
Frequently asked questions
Can I take Doxazosin with Penbutolol?
MediHelp rates the interaction as moderate. Doxazosin and Penbutolol 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 lower blood pressure, so using them together can produce greater hypotension than either alone. Dizziness, orthostatic hypotension and syncope are most likely after the first dose of doxazosin or after a dose increase.
How serious is the interaction between Doxazosin and Penbutolol?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start doxazosin at a low dose at bedtime and titrate slowly. Monitor standing and sitting blood pressure and warn the patient about postural dizziness.
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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