Amiloride is a Na+ channel blocker and has been used as a diuretic. It mainly inhibits the exchange of Na+-K+ and Na+-H+ in the distal tubule and collecting duct of the kidney, thus increasing the excretion of Na+ and water, reducing the excretion of K+ and H+. Recent studies have found a significant increase in urine uPA in patients with massive proteinuria.Urine uPA concentration were positively correlated with urinary protein and decreased with remission of proteinuria. In children and adults with nephrotic syndrome,as well as rat with proteinuria induced by puromycin amino-nucleoside, amiloride can inhibit uPA concentration in urine, which may be one of the mechanisms of amiloride in reducing proteinuria.
This study is a prospective , crossover, open-Label study. All patients need to be on an angiotensin converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB) daily at least four weeks prior to the study. The baseline data would be recorded. Patients enrolled will receive either amiloride or hydrochlorothiazide first for 8 weeks.Hydrochlorothiazide, a similar diuretic as amiloride, but not inhibiting urokinase plasminogen activator receptor (uPAR), will be used as a control. Then the patients will discontinue amiloride or hydrochlorothiazide for a washout for 4 weeks, but continue with the ACE inhibitor or ARB. After that patients will cross over to receive another medication for another 8 weeks. We aim to evaluate the effect and safety of Amiloride in decreasing proteinuria for patients with chronic kidney disease.
