Diuretics Flashcards
The most powerful class of diuretics is ____?
Loop diuretics (ex. Furosemide and Bumetanide)
How do loop diuretics work?
Inhibition of the Na+/K+/2Cl- carrier, causing excretion of 15-25% of filtered Na+
What are loop diuretics used for?
Treatment of salt and water overload associated with acute pulmonary edema, chronic heart failure, cirrhosis of the liver, nephrotic syndrome, renal failure, HTN with poor renal function
What are the adverse effects of loop diuretics?
Excessive Na+ and water loss
Hypovolemia*
Hypokalemia*
Metabolic alkalosis
Hypomagnesaemia
Hyperuricemia*
Reduced renal perfusion
Hearing loss*
Rashes
Bone marrow depression
Contraindicated in sulfa allergies
What class of medications do Bendroflumethiazide and Hydrochlorothiazide belong to?
Thiazides
What are thiazides used to treat?
HTN (preferred with normal renal function), mild heart failure, severe resistant edema, nephrogenic diabetes insipidus
What is the mechanism of action for thiazides?
Bind to the Cl- site of the distal tubular Na+/Cl- cotransporter, inducing natriuresis with loss of Na+ and Cl-
Stimulate renin secretion, leading to angiotensin formation and aldosterone secretion
Reduce Ca2+ excretion (unlike loop diuretics)
What are the adverse effects of thiazides?
Erectile dysfunction*
Hypochloremic alkalosis
Impaired glucose tolerance* (due to K+-ATPase activity)
Hyponatremia
Hypokalemia*
Rashes and blood dyscrasias are uncommon
Chlortalidone, Indapamide, and Metolazone are related to which drugs?
Thiazides
Spironolactone and Eplerenone belong to what class of diuretic?
Aldosterone antagonists (potassium sparing)
What are aldosterone antagonists used to treat?
Resistant essential HTN, heart failure, primary and secondary hyperaldosteronism
Inhibition of aldosterone inhibits what distal function?
Na+ retention and K+ secretion
Adverse effects of aldosterone antagonists include?
Hyperkalemia*
GI upset
Gynecomastia, menstrual disorders, and testicular atrophy (less with eplerenone)*
What is the mechanism of action of triamterene and amiloride?
Inhibit Na+ reabsorption in the collecting tubules by blocking aldosterone-regulated channels
What adverse effects are associated with use of triamterene and amiloride?
Hyperkalemia*
GI upset
What type of diuretic is Mannitol classified as?
An osmotic diuretic
When are osmotic diuretics used?
In acute renal failure and for treating acutely raised intracranial or intraocular pressure
What adverse effects are seen with osmotic diuretic use?
Increased risk for precipitating left ventricular failure (due to water loss in cardiomyocytes)*
Headache
Nausea
Vomiting
