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Drug interactions

Felodipine + Phenoxybenzamine

Severity: Moderate

Felodipine 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 causes irreversible alpha-blockade and marked vasodilation, and felodipine adds to the blood pressure lowering. Orthostatic hypotension and reflex tachycardia may be pronounced.

What this interaction means in plain words

Felodipine 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.

Evidence level: Low

Why it happens

Additive pharmacodynamic vasodilation from alpha-adrenergic blockade and calcium channel blockade.

What to do

Monitor supine and standing blood pressure and heart rate, and adjust doses accordingly. Counsel patients on slow position changes.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Felodipine with Phenoxybenzamine?

MediHelp rates the interaction as moderate. Felodipine 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 causes irreversible alpha-blockade and marked vasodilation, and felodipine adds to the blood pressure lowering. Orthostatic hypotension and reflex tachycardia may be pronounced.

How serious is the interaction between Felodipine 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 supine and standing blood pressure and heart rate, and adjust doses accordingly. Counsel patients on slow position changes.

What other medicines interact with Felodipine?

MediHelp also lists interactions of Felodipine with, for example, Itraconazole, Aldesleukin, Amifostine. The full list is on the Felodipine page.

Full monographs, dosing and an interaction checker in the MediHelp app

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