Drug interactions
Fosinopril + Phenoxybenzamine
Severity: Moderate
Fosinopril 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. With an ACE inhibitor, blood pressure may fall excessively, particularly at the start of treatment or after dose increases.
What this interaction means in plain words
Fosinopril 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 pharmacodynamic hypotension from alpha-adrenergic blockade and renin-angiotensin system inhibition.
What to do
Monitor blood pressure and orthostatic symptoms when initiating or titrating either drug. Introduce at low doses and titrate gradually.
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 Fosinopril
- Aliskiren + Fosinopril Contraindicated
- Fosinopril + Protein a column Contraindicated
- Fosinopril + Sacubitril / valsartan Contraindicated
- Fosinopril + Sacubitril-valsartan Contraindicated
- Amifostine + Fosinopril Major
- Amiloride + Fosinopril Major
Frequently asked questions
Can I take Fosinopril with Phenoxybenzamine?
MediHelp rates the interaction as moderate. Fosinopril 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. With an ACE inhibitor, blood pressure may fall excessively, particularly at the start of treatment or after dose increases.
How serious is the interaction between Fosinopril 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 blood pressure and orthostatic symptoms when initiating or titrating either drug. Introduce at low doses and titrate gradually.
What other medicines interact with Fosinopril?
MediHelp also lists interactions of Fosinopril with, for example, Aliskiren, Protein a column, Sacubitril / valsartan. The full list is on the Fosinopril page.
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