Drug interactions
Hydrochlorothiazide + Mefenamic acid
Severity: Moderate
Hydrochlorothiazide and Mefenamic acid: 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
NSAIDs can reduce the diuretic and antihypertensive effect of thiazides and may add to renal risk in volume-depleted patients. Combining them can lead to reduced blood pressure control, fluid retention and impaired renal function.
What this interaction means in plain words
Hydrochlorothiazide and Mefenamic acid 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.
Hydrochlorothiazide belongs to Cardiovascular; Mefenamic acid belongs to Musculoskeletal.
Why it happens
NSAID inhibition of renal prostaglandins reduces renal blood flow and sodium excretion, opposing thiazide action and increasing nephrotoxic risk.
What to do
Monitor blood pressure, renal function, electrolytes and fluid status, especially in elderly or dehydrated patients. Keep patients hydrated and use the lowest NSAID dose for the shortest time.
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 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 Hydrochlorothiazide
Frequently asked questions
Can I take Hydrochlorothiazide with Mefenamic acid?
MediHelp rates the interaction as moderate. Hydrochlorothiazide and Mefenamic acid 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. NSAIDs can reduce the diuretic and antihypertensive effect of thiazides and may add to renal risk in volume-depleted patients. Combining them can lead to reduced blood pressure control, fluid retention and impaired renal function.
How serious is the interaction between Hydrochlorothiazide and Mefenamic acid?
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, renal function, electrolytes and fluid status, especially in elderly or dehydrated patients. Keep patients hydrated and use the lowest NSAID dose for the shortest time.
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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