Drug interactions
Chlorothiazide + Mefenamic acid
Severity: Moderate
Chlorothiazide 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 increase the risk of acute kidney injury in volume-depleted patients.
What this interaction means in plain words
Chlorothiazide 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.
Chlorothiazide belongs to Cardiovascular; Mefenamic acid belongs to Musculoskeletal.
Why it happens
NSAID inhibition of renal prostaglandins causes sodium and water retention and reduced renal perfusion, opposing the thiazide.
What to do
Monitor blood pressure, hydration and renal function; 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 Chlorothiazide
Frequently asked questions
Can I take Chlorothiazide with Mefenamic acid?
MediHelp rates the interaction as moderate. Chlorothiazide 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 increase the risk of acute kidney injury in volume-depleted patients.
How serious is the interaction between Chlorothiazide 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, hydration and renal function; 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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