Drug interactions
Losartan + Spironolactone
Severity: Major
Losartan 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
Angiotensin receptor blockers reduce aldosterone secretion and, together with spironolactone, markedly decrease renal potassium excretion. This can cause clinically significant and occasionally life-threatening hyperkalemia, especially with renal impairment, diabetes or older age.
What this interaction means in plain words
Losartan 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.
Losartan belongs to Cardiovascular; Spironolactone belongs to Cardiovascular.
Why it happens
Dual suppression of the renin-angiotensin-aldosterone axis, with ARB-reduced aldosterone production and spironolactone receptor blockade, reduces renal potassium excretion.
What to do
Check serum potassium and creatinine at baseline, within about one week of starting or changing doses, and regularly afterwards. Avoid potassium supplements and reduce or stop therapy if potassium rises significantly.
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 Spironolactone
- Amiloride + Spironolactone Contraindicated
- Eplerenone + Spironolactone Contraindicated
- Spironolactone + Triamterene Contraindicated
- Abiraterone + Spironolactone Major
- Aceclofenac + Spironolactone Major
- Acemetacin + Spironolactone Major
Other interactions of Losartan
- Aliskiren + Losartan Contraindicated
- Losartan + Sparsentan Contraindicated
- Amifostine + Losartan Major
- Amiloride + Losartan Major
- Amlodipine-benazepril + Losartan Major
- Amlodipine-hydrochlorothiazide-valsartan + Losartan Major
Frequently asked questions
Can I take Losartan with Spironolactone?
MediHelp rates the interaction as major. Losartan 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. Angiotensin receptor blockers reduce aldosterone secretion and, together with spironolactone, markedly decrease renal potassium excretion. This can cause clinically significant and occasionally life-threatening hyperkalemia, especially with renal impairment, diabetes or older age.
How serious is the interaction between Losartan 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 at baseline, within about one week of starting or changing doses, and regularly afterwards. Avoid potassium supplements and reduce or stop therapy if potassium rises significantly.
What other medicines interact with Spironolactone?
MediHelp also lists interactions of Spironolactone with, for example, Amiloride, Eplerenone, Triamterene. The full list is on the Spironolactone page.
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