AuthorisedTherapeutic confirmatory (Phase III)Interventional

Achieve - ACetazolamide in patients with Heart failure, to decrease weight and relIEVE symptoms

Heart failure happens when the heart does not pump blood as well as it should. This often leads to fluid pooling in the body, causing sudden weight gain, swollen ankles, and shortness of breath. Doctors usually treat this with water tablets, known as diuretics, which encourage the kidneys to flush out fluid in urine. The Achieve trial looks at a tablet called acetazolamide (brand name Diamox). Researchers want to find out whether adding this medicine to standard treatment helps people lose at least 2 kg of excess fluid weight over five days. Participants use a smart digital scale at home that sends weight updates directly to the study team. The trial also tracks whether patients breathe more easily, feel better overall, and stay out of hospital over the following three months. The study is open to adults of all genders with heart failure.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Centre Hospitalier Universitaire De Montpellier

Enrolment target

1,050

Start

15 Jun 2026

Heart failure

What is this study about?

Heart failure is a long-term condition where the heart muscle struggles to pump blood effectively around the body. When blood flow slows down, fluid can back up into the lungs, legs, and abdomen. This fluid retention can make everyday activities difficult, leaving people tired, breathless, and uncomfortable due to swollen limbs.

Most patients take standard water tablets to help their kidneys remove this fluid. Even so, many people find that these standard tablets do not fully clear the fluid, or take a long time to work. The Achieve trial is testing a medicine called acetazolamide (Diamox) to see if it gives the kidneys an extra boost, helping patients get rid of surplus fluid more quickly and safely.

The main goal of the study is to see how many people lose more than 2 kilograms (about 4.4 pounds) of water weight within the first five days. Participants are given a digital scale that automatically shares their weight with the medical team. Over the course of 90 days, the researchers will also check if this approach relieves breathlessness, improves everyday quality of life, and prevents emergency hospital readmissions.

Key takeaways

Tests whether adding Diamox tablets helps remove excess fluid in heart failure.
Aims for a safe fluid weight loss of over 2 kg in the first five days.
Uses a smart scale to monitor your weight from home.
Tracks improvements in breathlessness and overall wellbeing over 90 days.
Open to adults aged 18 and older with heart failure fluid build-up.

Who may be eligible?

This trial is open to adults aged 18 and over who have been diagnosed with heart failure and are currently troubled by fluid retention. It welcomes both men and women.

To be considered, participants generally need to have signs that fluid is building up in their body. This might include noticeable swelling in the legs, sudden weight gain from water retention, or worsening breathlessness that requires medical support.

Not everyone with heart failure will be suitable. Doctors will check your medical history, your kidney health, and your current prescription medicines to make sure that taking acetazolamide alongside your usual treatments is safe for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or over.
I have been diagnosed with heart failure.
I am experiencing fluid build-up, such as swollen ankles or sudden weight gain.
I am able to swallow tablets.
I am willing to weigh myself daily at home using a digital scale.

Answer every question to see your result.

What does participation involve?

If you take part, you will be assigned to a treatment group to take either the study tablet (Diamox 250mg) or standard care alongside your regular heart medicines. You will be provided with a special digital scale to weigh yourself at home, which automatically sends your readings to the clinical team. During the first five days, doctors will closely track your weight, check your blood pressure, and test your blood and urine to see how effectively your kidneys are clearing salt and fluid. You will also complete short questionnaires about your breathing and daily wellbeing. Follow-up reviews will happen around day 5, day 15, and day 90 (three months) to monitor your symptoms and check that you have not needed emergency hospital care. Your total time in the study is about 90 days.

Potential risks and benefits

Taking part may help clear excess fluid from your body more rapidly, which could ease breathlessness and help you move around more comfortably. It also provides extra medical monitoring of your condition. However, all medicines carry potential risks. Diamox can cause mild side effects such as a tingling sensation in your fingers or toes, needing to urinate more frequently, or temporary changes in your body's salt levels, which will be monitored through routine blood tests. Joining the trial is entirely voluntary. You can choose to leave the study at any time without giving a reason, and your regular NHS care will continue as normal.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
France

Common questions

What is acetazolamide (Diamox)?

Diamox is an established medicine that works on the kidneys in a different way from regular water tablets, helping the body flush out extra bicarbonate and water.

Do I have to stop taking my regular heart tablets?

No. The study tablet is intended to be taken alongside your usual heart failure medications, not to replace them.

How does the home weighing scale work?

You step on the scale each morning as instructed. The device securely and automatically sends your weight reading to the research team so they can monitor your progress remotely.

How long will I be in the study?

The active trial medication and daily weight checks take place during the first few days, with occasional check-ins continuing up to day 90 (about three months).

What happens if I feel unwell during the trial?

You will be given direct contact details for the study team. If your symptoms worsen or you feel unwell, you can reach out to them or your normal healthcare team straight away.