Drug interactions
Diltiazem + Phentolamine
Severity: Moderate
Diltiazem and Phentolamine: 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 through vasodilation, so combined use can cause additive hypotension and reflex tachycardia.
What this interaction means in plain words
Diltiazem and Phentolamine 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.
Diltiazem belongs to Cardiovascular; Phentolamine belongs to Cardiovascular.
Why it happens
Additive vasodilation through alpha-adrenergic blockade and calcium channel blockade.
What to do
Monitor blood pressure and heart rate during phentolamine use and reduce doses if 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 Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Other interactions of Phentolamine
Frequently asked questions
Can I take Diltiazem with Phentolamine?
MediHelp rates the interaction as moderate. Diltiazem and Phentolamine 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 through vasodilation, so combined use can cause additive hypotension and reflex tachycardia.
How serious is the interaction between Diltiazem and Phentolamine?
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 heart rate during phentolamine use and reduce doses if hypotension occurs.
What other medicines interact with Diltiazem?
MediHelp also lists interactions of Diltiazem with, for example, Flibanserin, Ivabradine, Lomitapide. The full list is on the Diltiazem page.
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