Potassium Sparing Diuretics

Question 1

What are some of the drugs in this class and their action?

Answer 1

A. Aldosterone Receptor Blockers: spironolactone, eplerenone)

B. ENac Channel blockers:
( amiloride, triamterene)

Both result in increased urinary excretion of Na (they work on the collecting duct)

Question 2

What are their indications?

Answer 2

1. They are used in conjunction with other diuretics like thiazides in the treatment of hypertension to reduce potassium wasting
2. Spironolactone can be used to treat secondary (and primary) hyperaldosteronism due to liver failure (or increased RAAS)
3. Heart failure: spironolactone have been shown to decrease mortality rate in patients with heart failure by decreasing cardiac tissue remodeling which occurs as a compensatory mechanism
4. Can be used when other diuretics like loop or thiazide diuretics are contraindicated

Question 3

What are their side effects?

Answer 3

Spironolactone side effects:
1. it frequently causes GI upsets and can lead to peptic ulcers.
2. it can cause gynacomastia in males and menstrual irregularities in females.
3. it can cause hyperkalemia (which can lead to arrhythmias)

Triamterene can cause leg cramps and the possibility of increased blood urea nitrogen as well as uric acid and K retention.

Question 4

What are some combinations?

Answer 4

1. Triamterene — hydrochlorothiazide (dyazide, maxzide ): among the safest drugs to use, even though it’s a thiazide, it does not cause potassium wasting due to triamterene, it changes the color of urine to blue-green.
2. Bisoprolol-hydrochlorothiazide (Ziac): it can cause dizziness, headaches, diarrhea and fatigue
3. Amiloride 5mg — hydrochlorothiazide 50mg (moduretic): used for moderate HTN or edema