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Study on Amiloride for Treating Nephrogenic Diabetes Insipidus in Bipolar Disorder Patients on Long-term Lithium Therapy

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What is this trial about?

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

This clinical trial is focused on studying the effects of the medication amiloride for patients who have been treated with lithium for at least five years for bipolar disorder and are experiencing a condition known as nephrogenic diabetes insipidus. Nephrogenic diabetes insipidus is a condition where the kidneys are unable to concentrate urine, leading to excessive urination and thirst. The purpose of the study is to determine if amiloride can help reduce the urine concentration defect in these patients.

Participants in the study will receive either amiloride or a placebo and will be monitored over a period of time to assess changes in their condition. The study will last for several months, with key assessments occurring at 2, 6, and 12 months. During this time, researchers will evaluate various factors such as changes in urine concentration, the number of times participants need to urinate at night, their level of thirst, and overall quality of life. Additionally, the study will monitor kidney function and mood changes to ensure the safety and effectiveness of the treatment.

The trial aims to provide valuable insights into whether amiloride can be a beneficial treatment for managing nephrogenic diabetes insipidus in patients with bipolar disorder who are on long-term lithium therapy. By participating in this study, researchers hope to improve the understanding of how to better manage this condition and enhance the quality of life for affected individuals.

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

    Joining the study

    Upon joining the study, eligibility is confirmed based on criteria such as age between 18 and 70 years, having bipolar disorder, and being treated with lithium for at least 5 years.

    A urine concentration defect must be present, defined by a maximal urine osmolality of less than 600 mOsm/kg.

  2. Step 2

    Initial assessment

    Before starting the treatment, an initial assessment is conducted to measure baseline values for urine osmolality, nocturnal voids, thirst intensity, quality of life, kidney function, mood, anxiety, and sleep quality.

    These assessments help in comparing changes over the course of the study.

  3. Step 3

    Treatment phase

    The treatment involves taking amiloride orally. The specific dosage and frequency are determined by the study protocol.

    The primary goal is to observe the effect of amiloride on reducing the urine concentration defect over a 2-month period.

  4. Step 4

    2-month evaluation

    After 2 months of treatment, the primary endpoint is evaluated by measuring the percentage change in maximal urine osmolality.

    Secondary assessments include changes in nocturnal voids, thirst intensity, quality of life, kidney function, mood, anxiety, sleep quality, and plasma lithium levels.

  5. Step 5

    Extended monitoring

    Further evaluations occur at 6 and 12 months to monitor long-term effects and tolerances.

    These include the same assessments as the 2-month evaluation, with additional monitoring for any hospital admissions due to mood changes.

  6. Step 6

    Completion of study

    The study is estimated to conclude by January 11, 2026.

    Final assessments are conducted to gather comprehensive data on the treatment's impact over the entire study period.

Who can join the trial?

5 criteria

  • Adults between 18 and 70 years old.
  • Patient with bipolar disorder, which is a mental health condition that affects mood.
  • Patient treated with lithium for at least 5 years. Lithium is a medication used to treat bipolar disorder.
  • Patient with a urine concentration defect, meaning their urine cannot concentrate properly. This is defined by a maximal urine osmolality of less than 600 mOsm/kg. Osmolality is a measure of how concentrated the urine is.
  • Woman of childbearing age must agree to use an effective contraceptive method for 12 months.

Who cannot join the trial?

3 criteria

  • Patients who have not been treated with lithium carbonate for at least 5 years.
  • Patients who do not have a problem with their urine concentration. This means their body is not having trouble concentrating urine.
  • Patients who do not have a condition called nephrogenic diabetes insipidus. This is a condition where the kidneys cannot concentrate urine properly, leading to frequent urination and thirst.
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Investigated drugs

Amiloride is a medication used in this trial to treat nephrogenic diabetes insipidus in patients who are also being treated with lithium for bipolar disorder. The study aims to show that amiloride can help reduce the urine concentration defect caused by lithium treatment.

What is already known about the treatment

Amiloride – Amiloride is administered orally in tablet form. It is currently being studied in clinical trials for its effectiveness in treating nephrogenic diabetes insipidus in patients with bipolar disorder who have been on lithium treatment for at least five years. The main therapeutic indication is to address the urine concentration defect caused by lithium. At the molecular level, amiloride works by blocking sodium channels in the kidneys, which helps to reduce urine output and improve urine concentration. It is classified as a potassium-sparing diuretic.

Investigated diseases

  • Bipolar Disorder

    Bipolar disorder is a mental health condition characterized by extreme mood swings that include emotional highs (mania or hypomania) and lows (depression). During manic phases, individuals may feel euphoric, full of energy, or unusually irritable, while depressive phases can lead to feelings of sadness, hopelessness, and a lack of interest in most activities. These mood swings can affect sleep, energy, activity, judgment, behavior, and the ability to think clearly. The frequency and intensity of these episodes can vary greatly from person to person. Bipolar disorder is a lifelong condition, but mood swings and other symptoms can be managed with a treatment plan.

  • Nephrogenic Diabetes Insipidus

    Nephrogenic diabetes insipidus is a condition where the kidneys are unable to concentrate urine, leading to excessive urination and thirst. This occurs because the kidneys do not respond properly to the hormone vasopressin, which normally helps the body retain water. As a result, individuals with this condition produce large amounts of dilute urine and may become dehydrated if they do not drink enough fluids. It can be caused by genetic factors or acquired due to certain medications or kidney disorders. The condition can lead to complications if not managed properly, but it does not affect blood sugar levels like diabetes mellitus.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-515018-42-00Protocol codeAPHP200042Estimated enrolment148 patientsSponsorAssistance Publique Hopitaux De Paris

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