In short
Clinical trials are investigating Amiloride in people with lithium-treated bipolar disorder and in patients with autosomal dominant polycystic kidney disease. These studies look at whether Amiloride can improve urine concentration problems or affect arterial stiffness, and they measure both benefit and study safety in controlled settings.
Key points
- Clinical trials investigating Amiloride are looking at two different patient groups. One study enrolled people with bipolar disorder who had taken lithium for at least 5 years and had a urine concentration defect. The other study enrolled people with autosomal dominant polycystic kidney disease. The trials were done in Phase 2 and Phase 3, so they examined both early benefit and larger-scale effects. Main outcomes included maximal urine osmolality and pulse wave velocity, which help show urine concentrating ability and arterial stiffness. Both studies were completed.
Trial overview
Two interventional studies investigated Amiloride in different patient groups. Both studies were completed, and both used a comparison with placebo or another control treatment.
Lithium-related urine concentration defect study
The first study, NCT05044611, was a Phase 2 randomized controlled trial called AMIND, which studied people treated with lithium carbonate for bipolar disorder for at least 5 years and who had a urine concentration defect. The study asked whether Amiloride could reduce the urine concentration defect in patients who had nephrogenic diabetes insipidus, a condition where the kidneys cannot concentrate urine normally.
This trial compared Amiloride with placebo and included oral Amiloride doses of 10 mg and 20 mg. The study enrolled 148 participants and followed them for a 2-month treatment period.
Autosomal Dominant Polycystic Kidney Disease study
The second study, NCT05228574, was a Phase 3 interventional trial called the Trampoline study in people with Autosomal Dominant Polycystic Kidney Disease. The study tested whether Amiloride could change the effect of a high-salt diet on arterial stiffness and whether it could reduce arterial stiffness in both high-salt and low-salt settings.
This trial compared Amiloride with control conditions that included potato starch placebo and sodium chloride supplementation. It enrolled 54 participants and was completed.
Main outcomes measured
In the lithium-related trial, the primary endpoint was the percentage change in maximal urine osmolality before and after the 2-month treatment period. Urine osmolality is a measure of how concentrated the urine is, so this outcome shows whether the kidneys can hold on to water better after treatment.
In the ADPKD trial, the primary outcomes were differences in pulse wave velocity between the high-salt and placebo groups, and before versus after Amiloride treatment in both groups. Pulse wave velocity is a test used to estimate arterial stiffness, which means how rigid the arteries are.
Study design and phases
Both studies were interventional, which means the researchers gave a treatment and then measured the results. The lithium-related study was Phase 2, while the ADPKD study was Phase 3.
These phases matter because Phase 2 studies often look for early signs that a treatment may work, while Phase 3 studies usually test the treatment in a larger group and compare results more broadly.
Who participated
The lithium-related study focused on adults already treated with lithium carbonate for bipolar disorder for at least 5 years and with a urine concentration defect. This means the study was not for all people with bipolar disorder, but for a specific group with kidney-related urine problems after long-term lithium use.
The ADPKD study focused on people with autosomal dominant polycystic kidney disease. The trial did not list extra participant details in the source data, but it clearly targeted this kidney disease group.