Drug interactions
Fosinopril-hydrochlorothiazide + Spironolactone
Severity: Major
Fosinopril-hydrochlorothiazide and Spironolactone: major interaction.
Last updated Sources: US FDA label
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
Spironolactone and ACE inhibitors both reduce potassium excretion and together can cause serious hyperkalemia, especially with renal impairment, diabetes or older age. The thiazide offsets this only partly.
What this interaction means in plain words
Fosinopril-hydrochlorothiazide and Spironolactone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fosinopril-hydrochlorothiazide belongs to Cardiovascular; Spironolactone belongs to Cardiovascular.
Why it happens
Additive suppression of aldosterone effect (ACE inhibition plus mineralocorticoid receptor antagonism) reducing potassium excretion.
What to do
Check serum potassium and creatinine within the first week and regularly thereafter, and avoid potassium supplements. Reduce or stop spironolactone if potassium rises above safe limits.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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 Spironolactone
- Amiloride + Spironolactone Contraindicated
- Eplerenone + Spironolactone Contraindicated
- Spironolactone + Triamterene Contraindicated
- Abiraterone + Spironolactone Major
- Aceclofenac + Spironolactone Major
- Acemetacin + Spironolactone Major
Frequently asked questions
Can I take Fosinopril-hydrochlorothiazide with Spironolactone?
MediHelp rates the interaction as major. Fosinopril-hydrochlorothiazide and Spironolactone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Spironolactone and ACE inhibitors both reduce potassium excretion and together can cause serious hyperkalemia, especially with renal impairment, diabetes or older age. The thiazide offsets this only partly.
How serious is the interaction between Fosinopril-hydrochlorothiazide and Spironolactone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check serum potassium and creatinine within the first week and regularly thereafter, and avoid potassium supplements. Reduce or stop spironolactone if potassium rises above safe limits.
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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