Drug interactions
Phentolamine + Quinapril
Severity: Moderate
Phentolamine and Quinapril: 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
Both drugs lower blood pressure, and together they may cause an exaggerated hypotensive response, especially after the first dose of the ACE inhibitor. Dizziness and syncope may result.
What this interaction means in plain words
Phentolamine and Quinapril 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 hypotension from alpha-blockade and ACE inhibition.
What to do
Monitor blood pressure, particularly after the first quinapril dose or dose increases, and start at a low dose. Reduce 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 Phentolamine
Frequently asked questions
Can I take Phentolamine with Quinapril?
MediHelp rates the interaction as moderate. Phentolamine and Quinapril 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. Both drugs lower blood pressure, and together they may cause an exaggerated hypotensive response, especially after the first dose of the ACE inhibitor. Dizziness and syncope may result.
How serious is the interaction between Phentolamine and Quinapril?
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, particularly after the first quinapril dose or dose increases, and start at a low dose. Reduce either drug if symptomatic hypotension occurs.
What other medicines interact with Phentolamine?
MediHelp also lists interactions of Phentolamine with, for example, Alfuzosin, Avanafil, Doxazosin. The full list is on the Phentolamine page.
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