Drug interactions
Phenoxybenzamine + Verapamil
Severity: Moderate
Phenoxybenzamine and Verapamil: 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 causes long-lasting alpha blockade, and verapamil adds vasodilation. Together they can cause marked hypotension, dizziness and reflex tachycardia.
What this interaction means in plain words
Phenoxybenzamine and Verapamil 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 hypotensive pharmacodynamic effects from alpha-adrenergic blockade and calcium channel blockade.
What to do
Monitor supine and standing blood pressure when starting or changing doses. Reduce the dose of either drug if symptomatic hypotension occurs.
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 Verapamil
- Dofetilide + Verapamil Contraindicated
- Flibanserin + Verapamil Contraindicated
- Lomitapide + Verapamil Contraindicated
- Lonafarnib + Verapamil Contraindicated
- Pimozide + Verapamil Contraindicated
- Acebutolol + Verapamil Major
Frequently asked questions
Can I take Phenoxybenzamine with Verapamil?
MediHelp rates the interaction as moderate. Phenoxybenzamine and Verapamil 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 causes long-lasting alpha blockade, and verapamil adds vasodilation. Together they can cause marked hypotension, dizziness and reflex tachycardia.
How serious is the interaction between Phenoxybenzamine and Verapamil?
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 supine and standing blood pressure when starting or changing doses. Reduce the dose of either drug if symptomatic hypotension occurs.
What other medicines interact with Verapamil?
MediHelp also lists interactions of Verapamil with, for example, Dofetilide, Flibanserin, Lomitapide. The full list is on the Verapamil page.
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