Can a second diuretic boost recovery from heart failure?
NCT ID NCT06166654
First seen Aug 14, 2026 · Last updated Aug 14, 2026
Summary
This trial investigates whether adding either metolazone or acetazolamide to standard loop diuretics helps adults hospitalized with acute heart failure and fluid overload. Participants are randomly assigned to one of three treatment arms, and the study tracks days alive and out of the hospital within 30 days. The goal is to find the most effective strategy for reducing congestion and improving recovery.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Acetazolamide or metolazone added to standard loop diuretics
- What this could lead to
- If successful, this could identify a more effective diuretic combination to help people with acute heart failure recover faster and spend less time in the hospital.
- What could go wrong
- This is a phase 4 trial, but results may vary by patient. Risks include potential side effects from the added diuretics, such as kidney issues or electrolyte imbalances.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
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About 939 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Sep 2024
- Expected to finish
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Dec 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Age ≥ 18 years 2. Acute hospital admission with a clinical diagnosis of acute heart failure with volume overload. 3. Display risk of diuretic resistance, characterized by: 1. Daily loop-diuretics administration for a minimum of 7 days before admission, or 2. Insufficient decongestion observed in the preceding 24 hours (weight reduction \<500g or negative fluid balance \<1L) despite being treated with high-dose IV loop diuretic (equivalent to ≥120 mg IV furosemide within 24 hours). 4. Clinical signs of congestion, indicated by one or more of the following: pitting peripheral edema, ascites, elevated jugular venous pressure, or radiological/ultrasonic evidence of pulmonary congestion. Exclusion Criteria: 1. Acute coronary syndrome 2. Systolic blood pressure \<85 mmHg 3. Use of renal replacement therapy or ultrafiltration in-hospital before study inclusion 4. Treatment with acetazolamide or metolazone during the index hospitalization prior to randomization 5. Known allergy to any of the used drugs 6. Severe hypokalemia (\<2.5 mmol/l) or severe hyponatremia (\<125 mmol/l) 7. Severe hepatic impairment or liver cirrhosis 8. Known pregnancy
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
5 sites. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Aarhus university Hospital
RECRUITINGAarhus, 2650, Denmark
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Amager-Hvidovre Hospital
RECRUITINGHvidovre, Capital Region of Denmark, 2650, Denmark
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Bispebjerg Hospital
NOT_YET_RECRUITINGCopenhagen, 2400, Denmark
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Herlev-Gentofte hospital
RECRUITINGCopenhagen, 2730, Denmark
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Zealand University Hospital
RECRUITINGRoskilde, 2650, Denmark
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Other studies related to the condition(s) this trial covers.
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- Hospital heart pill may prevent repeat crises
- Heart failure fluid study: which furosemide method works best?
- Can MRI predict heart failure outcomes? new study investigates