K+ sparing diuretics are indicated for CHF and hypertension treatment.
These diuretics are typically combined with loop diuretics (or others), which tend to decrease body K+ to dangerously low levels. Using K+ sparing diuretics with these other K+ wasting drugs tends to keep a normal potassium reference range.
The K+ sparing diuretic spironolactone is often used in hyperaldosteronism, as it is a competitive aldosterone receptor antagonist.
These medications work in the cortical collecting tubule, to antagonize aldosterone or Na+ channels.
Spironolactone is a drug used for heart failure, ascites, hypertension, hypokalemia and hyperaldosteronism. This drug is also used as an antiandrogenic medication, as it blocks androgen binding through various mechanisms. Eplerenone is a very similar drug to spironolactone.
Spironolactone works by competing for intracellular mineralocorticoid receptors in the late distal tubule, or collecting tubule. This decreases the reabsorption of Na+ and water, while decreasing the secretion of K+.
Amiloride and triamterene are K+ sparing diuretics which act in the distal tubule or collecting tubule to decrease K+ loss by exerting their actions on epithelial sodium channels (ENaC).
These medications directly block epithelial Na+ channels (ENaC) to prevent its resorption in the collecting tubule in the kidneys. By blocking this channel, Na+ is not resorbed and K+ is not exchanged or wasted into the collecting tubule lumen.
These medications have the potential to cause hyperkalemia, as they prevent its secretion in the cortical collecting tubule. Hyperkalemia can lead to muscle weakness and fatal arrhythmias.
A side effect of Spironolactone administration is gynecomastia (male breasts), as this drug has antiandrogen effects and weak progesteronic effects (progesterone is linked to breast development).
Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.START QUIZ NOW
*Average video play time: 2-3 minutes
Unforgettable characters with concise but impactful videos (2-4 min each)