Drug interactions
Atenolol + Phenoxybenzamine
Severity: Moderate
Atenolol and Phenoxybenzamine: 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
Phenoxybenzamine produces long-lasting alpha-blockade and marked vasodilation, so adding atenolol can increase hypotension. In pheochromocytoma, beta-blockers are used after alpha-blockade is established, so the sequence of therapy matters.
What this interaction means in plain words
Atenolol and Phenoxybenzamine 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 hypotensive effects from irreversible alpha-blockade and beta-1 blockade.
What to do
Monitor blood pressure and heart rate closely, and check for orthostatic hypotension. In pheochromocytoma, start the beta-blocker only after adequate alpha-blockade is achieved.
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 Atenolol
- Amifostine + Atenolol Major
- Amiodarone + Atenolol Major
- Atenolol + Atenolol-chlorthalidone Major
- Atenolol + Betaxolol Major
- Atenolol + Bisoprolol Major
- Atenolol + Carvedilol Major
Frequently asked questions
Can I take Atenolol with Phenoxybenzamine?
MediHelp rates the interaction as moderate. Atenolol and Phenoxybenzamine 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. Phenoxybenzamine produces long-lasting alpha-blockade and marked vasodilation, so adding atenolol can increase hypotension. In pheochromocytoma, beta-blockers are used after alpha-blockade is established, so the sequence of therapy matters.
How serious is the interaction between Atenolol and Phenoxybenzamine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure and heart rate closely, and check for orthostatic hypotension. In pheochromocytoma, start the beta-blocker only after adequate alpha-blockade is achieved.
What other medicines interact with Atenolol?
MediHelp also lists interactions of Atenolol with, for example, Amifostine, Amiodarone, Atenolol-chlorthalidone. The full list is on the Atenolol page.
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