Potassium sparing diuretics

Potassium sparing diuretics:
• eg amiloride, spironolactone, triamterene
• action – act on distal tubule to cause excretion of sodium, bicarbonate and calcium and retention of potassium
• spironolactone blocks action of aldosterone in the distal nephron  retention of potassium and excretion of sodium
• triamterene and amiloride act by inhibiting sodium potassium exchange in distal tubule
• used to counteract potassium excretion caused by other diuretics
• indicated form hypertension and oedema
• adverse effects – hyperkalaemia, nausea, vomiting, diarrhoea