Drug interactions
Mefenamic acid + Spironolactone
Severity: Major
Mefenamic acid and Spironolactone: major 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
NSAIDs reduce renal prostaglandin synthesis and impair potassium excretion, which adds to the potassium-retaining effect of spironolactone. They can also blunt its diuretic and antihypertensive effect and worsen renal function. Hyperkalemia and acute kidney injury are the main concerns, particularly in older patients, those with CKD, or those taking ACE inhibitors.
What this interaction means in plain words
Mefenamic acid 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.
Mefenamic acid belongs to Musculoskeletal; Spironolactone belongs to Cardiovascular.
Why it happens
NSAID-induced suppression of prostaglandin-mediated renin and renal potassium handling combined with aldosterone antagonism produces hyperkalemia and reduced natriuresis.
What to do
Check serum potassium and creatinine within the first week and periodically thereafter. Avoid or limit NSAID duration, especially in renal impairment or heart failure.
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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Other interactions of Mefenamic acid
- Ketorolac intranasal + Mefenamic acid Contraindicated
- Ketorolac + Mefenamic acid Contraindicated
- Aceclofenac + Mefenamic acid Major
- Acemetacin + Mefenamic acid Major
- Acetylsalicylic acid + Mefenamic acid Major
- Alteplase + Mefenamic acid 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 Mefenamic acid with Spironolactone?
MediHelp rates the interaction as major. Mefenamic acid 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. NSAIDs reduce renal prostaglandin synthesis and impair potassium excretion, which adds to the potassium-retaining effect of spironolactone. They can also blunt its diuretic and antihypertensive effect and worsen renal function. Hyperkalemia and acute kidney injury are the main concerns, particularly in older patients, those with CKD, or those taking ACE inhibitors.
How serious is the interaction between Mefenamic acid 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 periodically thereafter. Avoid or limit NSAID duration, especially in renal impairment or heart failure.
What other medicines interact with Mefenamic acid?
MediHelp also lists interactions of Mefenamic acid with, for example, Ketorolac intranasal, Ketorolac, Aceclofenac. The full list is on the Mefenamic acid page.
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