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Effect of Acetazolamide Added to Standard Therapy on Weight Reduction and Symptom Relief in Patients with Heart Failure

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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on Heart failure, a condition in which the heart cannot pump blood as well as it should, leading to fluid buildup and shortness of breath. Participants will receive the medication acetazolamide, sold under the code name DIAMOX, in addition to their usual heart medicines such as furosemide, a drug that helps the kidneys remove excess fluid. The purpose of the study is to determine whether adding this medication helps reduce fluid overload and improve symptoms compared with standard therapy alone.

During the trial, individuals will take the study drug for a short period while their weight is measured each day using a connected scale that sends data through remote monitoring to the study team. Researchers will look at how much weight is lost, changes in breathing difficulty, and a blood test called NtproBNP, which rises when the heart is under stress. The study runs for a few weeks, with follow‑up visits to check health status and any need for urgent care or hospital visits.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline assessment (day 0)

    After joining the study, you undergo a baseline assessment that records your current weight, blood pressure, heart rate, and symptoms related to heart failure.

    Blood samples are taken to measure nt-probnp and other routine laboratory values.

    The information is entered into a remote monitoring system that will track changes during the trial.

  2. Step 2

    Start of study medication

    You begin taking acetazolamide (brand name DIAMOX) in addition to your usual heart failure medicines such as furosemide.

    The prescribed dose is 1000 mg per day, which corresponds to four 250 mg tablets taken orally once daily.

    The medication is continued for at least five days, with the possibility of continuation up to day 15 as directed by the study protocol.

  3. Step 3

    Daily weight monitoring

    Each morning you step on a connected scale that automatically transmits your weight to the remote monitoring system.

    The scale records weight changes and alerts the study team if the loss exceeds 2 kg, which is a key measure of the study’s primary outcome.

  4. Step 4

    Day 5 evaluation

    After five days of treatment, you undergo an evaluation that includes:

    • review of the weight data to determine if a loss of more than 2 kg has occurred,
    • a urine test (urinary ionogram) to assess diuretic effectiveness,
    • a blood test to measure changes in nt-probnp,
    • a questionnaire (EQ-5D-5L) to evaluate overall health status, and
    • a visual analogue scale (VAS) rating of dyspnea (shortness of breath).

    These assessments are performed either remotely or during a brief clinic visit, as specified by the study schedule.

  5. Step 5

    Day 15 follow‑up

    Approximately ten days after the day‑5 visit, you have a second follow‑up that repeats the clinical measurements (weight, blood pressure, heart rate, symptom scores) and the laboratory test for nt-probnp.

    The purpose is to observe any further changes after continued medication use.

  6. Step 6

    Day 90 safety check

    Around three months after the start of the study, you are contacted to report any unplanned emergency visits, hospitalizations, or deaths related to heart failure.

    This safety check helps determine longer‑term outcomes of the treatment.

Who can join the trial?

6 criteria

  • You must be 18 years old or older.
  • You must have a diagnosis of heart failure, regardless of whether your heart’s pumping ability (called left ventricular ejection fraction) is low, mildly reduced, or normal.
  • You must already be taking the regular medicines that are recommended for heart failure by the current European guidelines.
  • You must be using a remote monitoring system that records your weight each day with a connected scale (examples include Careline®, Optified‑self®, NewCard®, Implicity®).
  • You must have been taking the diuretic medicine furosemide at a dose of at least 20 mg per day for at least the past 30 days.
  • You must be currently in the hospital or visiting a doctor unexpectedly because of a sudden worsening (acute decompensation) of your heart failure.

Who cannot join the trial?

21 criteria

  • Unable to give consent or sign the consent form.
  • Has low cardiac output syndrome or cardiogenic shock (the heart cannot pump enough blood).
  • Currently taking acetazolamide or any other carbonic anhydrase inhibitor (including eye drops such as brinzolamide, dorzolamide, or methazolamide).
  • Not covered by public health insurance.
  • Declines to take part in the study (does not give consent).
  • Is under guardianship, legal protection, or is deprived of liberty (a legal guardian makes decisions).
  • Is pregnant or breastfeeding.
  • Is a prisoner or under legal protection.
  • Is a woman who could become pregnant and is not using an effective birth‑control method (such as birth‑control pills, implants, injections, patches, IUD, condoms with spermicide, abstinence, or a partner who cannot father children).
  • Cannot understand or follow the study instructions and follow‑up visits.
  • Is already participating in another interventional study.
  • Has a chronic ventricular assist device or has had a heart transplant.
  • Is taking lithium, valproic acid, or valpromide (medicines used for mood disorders).
  • Is taking high‑dose aspirin (more than 300 mg per day).
  • Has acute heart failure caused by a recent acute coronary syndrome (heart attack) within the past month.
  • Has severe chronic kidney failure or is on dialysis (kidney function measured by GFR less than 20 ml/min).
  • Has a history of kidney stones (renal colic), a condition called hyperchloremic acidosis, or a wheat allergy (other than celiac disease).
  • Has severe liver disease (shown by a blood test called PTT less than 50% or a Child‑Pugh score of C) or known adrenal insufficiency (the adrenal glands do not make enough hormones).
  • Cannot tolerate sulphonamides (a group of antibiotics).
  • Is allergic to acetazolamide or any of its inactive ingredients (excipient) such as calcium carbonate, wheat starch, gelatin, or magnesium stearate.
  • Is taking carbamazepine or quinidine‑type medicines (hydroquinidine, quinidine).
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Investigated drugs

  • Acetazolamide

    is a medication that helps the body get rid of extra fluid by increasing the amount of urine produced. In this trial, it is added to the usual heart‑failure medicines to see if it can improve decongestion, reduce weight, and relieve symptoms more quickly.

  • Furosemide

    is a commonly used diuretic that also helps the body eliminate excess fluid by making the kidneys produce more urine. In the study, participants have already been taking furosemide as part of their regular heart‑failure treatment, and the effect of adding acetazolamide to this regimen is being tested.

What is already known about the treatment

DIAMOX* 250mg Tablets - This medication is taken as an oral tablet that you swallow with water. It is an approved drug that has been studied for many years and is listed in medical references worldwide. It is mainly used to treat conditions such as glaucoma, altitude sickness, certain types of epilepsy, and fluid buildup, and in this trial it is being tested to help patients with heart failure reduce excess weight and symptoms. The drug works by blocking an enzyme called carbonic anhydrase, which lowers the amount of salt and water the kidneys keep, creating a mild diuretic effect; it belongs to the class of carbonic anhydrase inhibitor diuretics.

Investigated diseases

Heart failure - Heart failure is a condition where the heart cannot pump blood as well as it should. Over time, the heart’s pumping ability may become weaker, causing fluid to build up in the lungs and other parts of the body. This fluid accumulation can lead to swelling in the legs, shortness of breath, and feeling unusually tired. As the condition progresses, the symptoms can become more frequent and may affect daily activities.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-524344-35-00Protocol codeRECHMPL24_0295Estimated enrolment1 050 patientsSponsorCentre Hospitalier Universitaire De Montpellier

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