Potassium-sparing diuretic Flashcards
Indication
Potassium-sparing diuretic
Prevention of diuretic-induced hypokalaemia
Oedema due to heart failure, hepatic cirrhosis or nephrotic syndrome, as an adjunct to thiazide or loop diuretic
Hypertension
MOA
Potassium-sparing diuretics
Weak diuretic; inhibits sodium reabsorption in the distal tubule by blocking sodium channels. As a result, it interferes with sodium/potassium exchange and reduces urinary potassium excretion.
Precautions
Potassium-sparing diuretic
Hyperkalaemia—contraindicated if serum potassium concentration >5 mmol/L; avoid use or use cautiously if it is >3.5 mmol/L.
Debilitated patients with cardiopulmonary disease or uncontrolled diabetes—increased risk of hyperkalaemia and respiratory or metabolic acidosis.
Treatment with drugs that can increase potassium concentration, eg trimethoprim—increases risk of hyperkalaemia; avoid combination or monitor potassium concentration.
Adverse effects
Potassium-sparing diuretics
hyperkalaemia, hyponatraemia and hypochloraemia (especially when combined with thiazide diuretics), weakness, headache, nausea, vomiting, constipation, impotence, dizziness, muscle cramps
Nursing considerations
Potassium-sparing diuretic
This medicine is usually taken once daily in the morning. If you are taking it twice a day, take the first dose in the morning and the second dose before 6 pm.
You may feel dizzy on standing when taking this medicine. Get up gradually from sitting or lying to minimise this effect; sit or lie down if you become dizzy.
Do not take potassium supplements while you are taking this medicine unless your doctor tells you to.
Practice points
amiloride is not required routinely in patients taking thiazide or loop diuretics; reserve for use if hypokalaemia occurs (serum potassium <3.5 mmol/L)
may cause severe hyperkalaemia, especially in the presence of renal impairment or if used with ACE inhibitors, sartans, aldosterone antagonists or potassium supplements
