Drug interactions
Labetalol + Phentolamine
Severity: Moderate
Labetalol 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 a nonselective alpha blocker, and combining it with labetalol, which also has alpha and beta blocking effects, can cause marked hypotension. Tachycardia from phentolamine may be blunted by beta-blockade.
What this interaction means in plain words
Labetalol 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.
Labetalol belongs to Cardiovascular; Phentolamine belongs to Cardiovascular.
Why it happens
Additive alpha-adrenergic blockade and vasodilation.
What to do
Monitor blood pressure continuously during phentolamine use and titrate doses cautiously. In pheochromocytoma, ensure alpha-blockade is established before beta-blockade.
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 Labetalol
- Amifostine + Labetalol Major
- Amiodarone + Labetalol Major
- Atenolol-chlorthalidone + Labetalol Major
- Atenolol + Labetalol Major
- Betaxolol + Labetalol Major
- Bisoprolol + Labetalol Major
Other interactions of Phentolamine
Frequently asked questions
Can I take Labetalol with Phentolamine?
MediHelp rates the interaction as moderate. Labetalol 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 a nonselective alpha blocker, and combining it with labetalol, which also has alpha and beta blocking effects, can cause marked hypotension. Tachycardia from phentolamine may be blunted by beta-blockade.
How serious is the interaction between Labetalol 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 continuously during phentolamine use and titrate doses cautiously. In pheochromocytoma, ensure alpha-blockade is established before beta-blockade.
What other medicines interact with Labetalol?
MediHelp also lists interactions of Labetalol with, for example, Amifostine, Amiodarone, Atenolol-chlorthalidone. The full list is on the Labetalol page.
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