Drug interactions
Fosinopril-hydrochlorothiazide + Prazosin
Severity: Moderate
Fosinopril-hydrochlorothiazide and Prazosin: 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
Prazosin causes alpha-1 blockade and first-dose orthostatic hypotension, which may be greater when the patient is already taking an ACE inhibitor and diuretic. Syncope and falls are possible when starting or increasing the dose.
What this interaction means in plain words
Fosinopril-hydrochlorothiazide and Prazosin 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.
Fosinopril-hydrochlorothiazide belongs to Cardiovascular; Prazosin belongs to Genitourinary.
Why it happens
Additive vasodilation and volume-related blood pressure lowering from alpha-1 blockade, ACE inhibition and diuresis.
What to do
Start prazosin at a low dose at bedtime and monitor blood pressure and orthostatic symptoms. Consider reducing diuretic dose if volume depleted.
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-hydrochlorothiazide
- Aliskiren + Fosinopril-hydrochlorothiazide Contraindicated
- Dofetilide + Fosinopril-hydrochlorothiazide Contraindicated
- Fosinopril-hydrochlorothiazide + Protein a column Contraindicated
- Fosinopril-hydrochlorothiazide + Sacubitril / valsartan Contraindicated
- Aldesleukin + Fosinopril-hydrochlorothiazide Major
- Amifostine + Fosinopril-hydrochlorothiazide Major
Other interactions of Prazosin
- Alfuzosin + Prazosin Major
- Amifostine + Prazosin Major
- Avanafil + Prazosin Major
- Doxazosin + Prazosin Major
- Dutasteride-tamsulosin + Prazosin Major
- Phenoxybenzamine + Prazosin Major
Frequently asked questions
Can I take Fosinopril-hydrochlorothiazide with Prazosin?
MediHelp rates the interaction as moderate. Fosinopril-hydrochlorothiazide and Prazosin 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. Prazosin causes alpha-1 blockade and first-dose orthostatic hypotension, which may be greater when the patient is already taking an ACE inhibitor and diuretic. Syncope and falls are possible when starting or increasing the dose.
How serious is the interaction between Fosinopril-hydrochlorothiazide and Prazosin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start prazosin at a low dose at bedtime and monitor blood pressure and orthostatic symptoms. Consider reducing diuretic dose if volume depleted.
What other medicines interact with Fosinopril-hydrochlorothiazide?
MediHelp also lists interactions of Fosinopril-hydrochlorothiazide with, for example, Aliskiren, Dofetilide, Protein a column. The full list is on the Fosinopril-hydrochlorothiazide page.
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