Drug interactions
Metolazone + Torsemide
Severity: Major
Metolazone and Torsemide: major interaction.
Last updated Sources: US FDA label
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 combined with a loop diuretic produces sequential nephron blockade and a strong diuresis, which is sometimes used deliberately in diuretic resistance. It carries a substantial risk of severe hypokalemia, hyponatremia, hypomagnesemia, dehydration and renal impairment.
What this interaction means in plain words
Metolazone and Torsemide 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.
Metolazone belongs to Cardiovascular; Torsemide belongs to Cardiovascular.
Why it happens
Synergistic diuresis from blocking sodium reabsorption at the loop of Henle and the distal convoluted tubule.
What to do
Start with low doses and monitor electrolytes, creatinine, weight and blood pressure frequently, within the first few days. Replace potassium and magnesium as needed and limit the duration of combined use.
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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References
Other interactions of Metolazone
Other interactions of Torsemide
Frequently asked questions
Can I take Metolazone with Torsemide?
MediHelp rates the interaction as major. Metolazone and Torsemide 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. Metolazone combined with a loop diuretic produces sequential nephron blockade and a strong diuresis, which is sometimes used deliberately in diuretic resistance. It carries a substantial risk of severe hypokalemia, hyponatremia, hypomagnesemia, dehydration and renal impairment.
How serious is the interaction between Metolazone and Torsemide?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start with low doses and monitor electrolytes, creatinine, weight and blood pressure frequently, within the first few days. Replace potassium and magnesium as needed and limit the duration of combined use.
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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