Potassium-sparing diuretics to reduce blood pressure

Spironolactone is a mineralocorticoid receptor antagonist that is effective as add-on therapy in patients with elevated blood pressure (BP) that is resistant to first-line treatment. There is some evidence that spironolactone is more effective than beta blockers and alpha blockers when added to maximum doses of 3 BP-lowering drugsWilliams, 2015.

Rapid normalisation or reduction of BP in response to spironolactone therapy may indicate underlying primary aldosteronism.

Before starting a potassium-sparing diuretic, check the patient’s kidney function and plasma potassium concentration. Do not use potassium-sparing diuretics if potassium concentration is 5 mmol/L or more.

If a potassium-sparing diuretic is considered appropriate to reduce BP, start with a low dose and increase slowly as required. A suitable dose range is:

If spironolactone is not tolerated, use:

Spironolactone and amiloride can cause hyperkalaemia, particularly in patients with kidney disease, and in patients taking an angiotensin converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB). Check kidney function and serum potassium concentration 1 to 2 weeks after starting therapy.