Abstract
Amiloride is a potassium retaining diuretic and natriuretic which acts by reversibly
blocking luminal epithelial sodium channels (ENaCs) in the late distal tubule and
collecting duct. Amiloride is indicated in oedematous states, and for potassium
conservation adjunctive to thiazide or loop diuretics for hypertension, congestive heart
failure and hepatic cirrhosis with ascites. Historical studies on its use in hypertension
were poorly controlled and there is insufficient data on dose-response. It is clearly
highly effective in combination with thiazide diuretics where it counteracts the adverse
metabolic effects of the thiazides and its use in the Medical Research Council Trial of
Older Hypertensive Patients, demonstrated convincing outcome benefits on stroke and
coronary events. Recently it has been shown to be as effective as spironolactone in
resistant hypertension but there is a real need to establish its potential role in the
much larger number of patients with mild to moderate hypertension in whom there is a
paucity of information with amiloride particularly across an extended dose range.
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