Drug interactions
Nifedipine + Phenoxybenzamine
Severity: Moderate
Nifedipine 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 is an irreversible alpha-blocker, and with nifedipine the blood pressure lowering effects add together. Patients may develop marked orthostatic hypotension and reflex tachycardia, which is relevant in pheochromocytoma preparation.
What this interaction means in plain words
Nifedipine 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 vasodilation through alpha-adrenergic blockade and calcium channel blockade.
What to do
Monitor supine and standing blood pressure and heart rate when combining, and titrate doses gradually. Ensure adequate hydration and counsel on postural precautions.
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 Nifedipine
Frequently asked questions
Can I take Nifedipine with Phenoxybenzamine?
MediHelp rates the interaction as moderate. Nifedipine 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 is an irreversible alpha-blocker, and with nifedipine the blood pressure lowering effects add together. Patients may develop marked orthostatic hypotension and reflex tachycardia, which is relevant in pheochromocytoma preparation.
How serious is the interaction between Nifedipine 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 when combining, and titrate doses gradually. Ensure adequate hydration and counsel on postural precautions.
What other medicines interact with Nifedipine?
MediHelp also lists interactions of Nifedipine with, for example, Amifostine, Amlodipine-benazepril, Apalutamide. The full list is on the Nifedipine page.
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