Drug interactions
Metoprolol + Phentolamine
Severity: Moderate
Metoprolol and Phentolamine: 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
Phentolamine is an alpha-blocking vasodilator that can cause marked hypotension and reflex tachycardia. Metoprolol adds to the blood pressure lowering and blunts the compensatory heart rate response.
What this interaction means in plain words
Metoprolol and Phentolamine 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.
Metoprolol belongs to Cardiovascular; Phentolamine belongs to Cardiovascular.
Why it happens
Additive hypotensive effect from alpha-adrenergic blockade and beta-1 blockade.
What to do
Monitor blood pressure and heart rate closely when phentolamine is given to a patient on metoprolol. Titrate the phentolamine dose cautiously.
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 Metoprolol
- Metoprolol + Thioridazine Contraindicated
- Amifostine + Metoprolol Major
- Amiodarone + Metoprolol Major
- Atenolol-chlorthalidone + Metoprolol Major
- Atenolol + Metoprolol Major
- Betaxolol + Metoprolol Major
Other interactions of Phentolamine
Frequently asked questions
Can I take Metoprolol with Phentolamine?
MediHelp rates the interaction as moderate. Metoprolol and Phentolamine 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. Phentolamine is an alpha-blocking vasodilator that can cause marked hypotension and reflex tachycardia. Metoprolol adds to the blood pressure lowering and blunts the compensatory heart rate response.
How serious is the interaction between Metoprolol and Phentolamine?
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 when phentolamine is given to a patient on metoprolol. Titrate the phentolamine dose cautiously.
What other medicines interact with Metoprolol?
MediHelp also lists interactions of Metoprolol with, for example, Thioridazine, Amifostine, Amiodarone. The full list is on the Metoprolol page.
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