Drug interactions
Metolazone + Triamterene
Severity: Moderate
Metolazone and Triamterene: 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
Metolazone lowers serum potassium while triamterene retains it, so potassium may be balanced, too low or too high. Combined use also enhances diuresis and can cause hyponatraemia and volume depletion.
What this interaction means in plain words
Metolazone and Triamterene 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.
Metolazone belongs to Cardiovascular; Triamterene belongs to Cardiovascular.
Why it happens
Opposing effects on potassium: metolazone increases distal potassium loss while triamterene blocks ENaC and reduces potassium secretion.
What to do
Monitor serum potassium, sodium and renal function regularly, especially in the elderly or with renal impairment. Avoid potassium supplements unless hypokalaemia is confirmed.
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 Metolazone
Other interactions of Triamterene
- Amiloride + Triamterene Contraindicated
- Eplerenone + Triamterene Contraindicated
- Potassium citrate / citric acid + Triamterene Contraindicated
- Potassium citrate + Triamterene Contraindicated
- Spironolactone + Triamterene Contraindicated
- Aceclofenac + Triamterene Major
Frequently asked questions
Can I take Metolazone with Triamterene?
MediHelp rates the interaction as moderate. Metolazone and Triamterene 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. Metolazone lowers serum potassium while triamterene retains it, so potassium may be balanced, too low or too high. Combined use also enhances diuresis and can cause hyponatraemia and volume depletion.
How serious is the interaction between Metolazone and Triamterene?
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 serum potassium, sodium and renal function regularly, especially in the elderly or with renal impairment. Avoid potassium supplements unless hypokalaemia is confirmed.
What other medicines interact with Metolazone?
MediHelp also lists interactions of Metolazone with, for example, Amifostine, Amlodipine-hydrochlorothiazide-valsartan, Amlodipine-olmesartan-hydrochlorothiazide. The full list is on the Metolazone page.
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