What are potassium-sparing diuretics?

From the Guidelines

Potassium-sparing diuretics should be used with caution and only considered if there is persisting diuretic-induced hypokalaemia despite concomitant ACE inhibitor therapy, or in severe heart failure, despite concomitant ACE inhibition plus low-dose spironolactone 1.

Key Considerations

• The use of potassium-sparing diuretics, such as triamterene, amiloride, and spironolactone, should be monitored by repeated measurements of serum creatinine and potassium 1.
• A practical approach is to measure serum creatinine and potassium every 5–7 days after initiation of treatment until the values are stable, and thereafter, measurements can be made every 3–6 months 1.
• The combination of potassium-sparing diuretics and ACE inhibitors was previously regarded as potentially dangerous, but recent studies suggest that spironolactone at dosages of 50–100 mg may result in rapid weight reduction without hyperkalaemia in patients not responding to loop diuretics and ACE inhibition 1.

Medication Options

• Spironolactone: 25-100mg daily, with higher doses occasionally used with close monitoring 1.
• Amiloride: 5-10mg daily 1.
• Triamterene: 50-100mg daily 1.

Important Side Effects

• Hyperkalemia, especially in patients with kidney dysfunction or those taking ACE inhibitors or ARBs 1.
• Gynecomastia in men due to the anti-androgenic properties of spironolactone 1.
• Headache, dizziness, and gastrointestinal disturbances 1.

From the FDA Drug Label

Triamterene Capsules are potassium-sparing diuretics. Amiloride HCl is a potassium-sparing diuretic.

Potassium-sparing diuretics are a class of diuretics that include triamterene and amiloride. These medications help the body get rid of excess fluid but spare potassium from being lost.

• Key characteristics:
  • Help eliminate excess fluid
  • Spare potassium from being lost
  • Include triamterene and amiloride as examples 2 3

From the Research

Potassium-Sparing Diuretics

• Potassium-sparing diuretics, such as spironolactone and amiloride, are effective in maintaining normal serum potassium levels in peritoneal dialysis patients 4.
• These diuretics work by increasing the excretion of sodium and water while retaining potassium, which can help correct hypokalemia in patients with kidney disease 5.
• The use of potassium-sparing diuretics has been shown to decrease the need for oral potassium supplements in peritoneal dialysis patients 4.

Mechanism of Action and Effects

• Potassium-sparing diuretics have a direct action on the tubular sites of the nephron, enhancing the renal excretion of sodium and water 6.
• The antihypertensive effects of potassium-sparing diuretics, such as triamterene, amiloride, spironolactone, and eplerenone, have been studied, with spironolactone showing the greatest antihypertensive potency 7.
• The use of potassium-sparing diuretics can also increase serum potassium levels, with spironolactone causing greater hyperkalemia than amiloride 7.

Clinical Utility and Guidelines

• The routine prophylactic use of potassium-sparing diuretics in combination with non-potassium-retaining diuretics for the treatment of hypertension and edematous states is not justified 8.
• However, potassium-sparing diuretics may be useful in patients with resistant hypertension, primary and secondary hyperaldosteronism, and systolic heart failure 6.
• The role of potassium-sparing diuretics in the management of hypokalemia in peritoneal dialysis patients remains unclear, with limited data on efficacy and safety 5.