Drug interactions
Captopril-hydrochlorothiazide + Phentolamine
Severity: Moderate
Captopril-hydrochlorothiazide 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
Phentolamine is a potent alpha-blocking vasodilator and can cause marked hypotension, which may be exaggerated with captopril and hydrochlorothiazide. Tachycardia and syncope may occur.
What this interaction means in plain words
Captopril-hydrochlorothiazide 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.
Captopril-hydrochlorothiazide belongs to Cardiovascular; Phentolamine belongs to Cardiovascular.
Why it happens
Additive vasodilatory and hypotensive effects from alpha-adrenergic blockade and ACE inhibition plus diuresis.
What to do
Monitor blood pressure closely, with the patient supine during administration. Correct volume depletion first and titrate phentolamine cautiously.
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 Captopril-hydrochlorothiazide
- Aliskiren + Captopril-hydrochlorothiazide Contraindicated
- Captopril-hydrochlorothiazide + Dofetilide Contraindicated
- Captopril-hydrochlorothiazide + Sacubitril / valsartan Contraindicated
- Aceclofenac + Captopril-hydrochlorothiazide Major
- Aldesleukin + Captopril-hydrochlorothiazide Major
- Amifostine + Captopril-hydrochlorothiazide Major
Other interactions of Phentolamine
Frequently asked questions
Can I take Captopril-hydrochlorothiazide with Phentolamine?
MediHelp rates the interaction as moderate. Captopril-hydrochlorothiazide 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. Phentolamine is a potent alpha-blocking vasodilator and can cause marked hypotension, which may be exaggerated with captopril and hydrochlorothiazide. Tachycardia and syncope may occur.
How serious is the interaction between Captopril-hydrochlorothiazide 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 closely, with the patient supine during administration. Correct volume depletion first and titrate phentolamine cautiously.
What other medicines interact with Captopril-hydrochlorothiazide?
MediHelp also lists interactions of Captopril-hydrochlorothiazide with, for example, Aliskiren, Dofetilide, Sacubitril / valsartan. The full list is on the Captopril-hydrochlorothiazide page.
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