Drug interactions
Hydrochlorothiazide + Tolfenamic acid
Severity: Moderate
Hydrochlorothiazide and Tolfenamic 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 such as tolfenamic acid can reduce the diuretic and antihypertensive effect of hydrochlorothiazide. The combination also increases the risk of acute kidney injury, particularly with dehydration, and NSAIDs may raise potassium.
What this interaction means in plain words
Hydrochlorothiazide and Tolfenamic 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; Tolfenamic acid belongs to Musculoskeletal.
Why it happens
NSAID inhibition of renal prostaglandin synthesis causes sodium and water retention and reduces renal perfusion, opposing diuretic effects.
What to do
Monitor blood pressure, renal function and potassium, and use the lowest effective NSAID dose for the shortest time. Ensure adequate hydration.
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 Hydrochlorothiazide
Other interactions of Tolfenamic acid
Frequently asked questions
Can I take Hydrochlorothiazide with Tolfenamic acid?
MediHelp rates the interaction as moderate. Hydrochlorothiazide and Tolfenamic 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 such as tolfenamic acid can reduce the diuretic and antihypertensive effect of hydrochlorothiazide. The combination also increases the risk of acute kidney injury, particularly with dehydration, and NSAIDs may raise potassium.
How serious is the interaction between Hydrochlorothiazide and Tolfenamic 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 and potassium, and use the lowest effective NSAID dose for the shortest time. Ensure adequate hydration.
What other medicines interact with Hydrochlorothiazide?
MediHelp also lists interactions of Hydrochlorothiazide with, for example, Dofetilide, Amifostine, Amiodarone. The full list is on the Hydrochlorothiazide page.
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