Diuretics-2 (1) (1) Flashcards
What are inhibitors of carbonic anhydrase?
Examples include Acetazolamide, Dichlorphenamide, and Methazolamide. They abolish HCO3- reabsorption in the proximal tubule.
What are osmotic diuretics?
Examples include Glycerin, Isosorbide, Mannitol, and Urea. They primarily act in the loop of Henle to expand extracellular fluid volume, decrease blood viscosity, and inhibit renin release.
What are loop diuretics?
Examples include Furosemide, Bumetanide, Ethacrynic acid, and Torsemide. They inhibit the Na+-K+-2Cl- symporter.
What are thiazide and thiazide-like diuretics?
More than 11 types exist. The prototype is Hydrochlorothiazide. They inhibit the Na+-Cl- symporter and are used to treat hypertension and edema.
What are potassium-sparing diuretics?
Examples include Triamterene and Amiloride. They inhibit renal epithelial Na+ channels and enhance diuresis without potassium loss.
What are aldosterone antagonists?
Examples include Spironolactone and Eplerenone. They are a type of potassium-sparing diuretic.
What is the primary action site of thiazide diuretics?
They principally inhibit Na+-Cl- transport in the distal convoluted tubule (DCT) of the nephron.
What is the maximum sodium excretion achieved by thiazides?
The maximum excretion of filtered load of sodium is only 5%.
How do thiazides affect calcium excretion?
Chronically administered thiazides reduce Ca2+ excretion due to enhanced proximal reabsorption.
What is the effect of thiazides on renal blood flow?
Thiazides do not affect renal blood flow and variably decrease glomerular filtration rate (GFR).
What are the therapeutic uses of thiazides?
They treat hypertension, edema associated with congestive heart failure, hepatic cirrhosis, acute glomerulonephritis, nephrotic syndrome, chronic renal failure, and nephrolithiasis.
Fill in the blank: Thiazides are useful against _______ and osteoporosis.
nephrolithiasis
What is the mechanism of action of potassium-sparing diuretics?
They suppress epithelial Na+ channels in the luminal membrane of principal cells.
True or False: Potassium-sparing diuretics are usually used as sole agents for edema.
False
What effect do potassium-sparing diuretics have when coadministered with thiazides?
They enhance the diuretic and anti-hypertensive response and normalize plasma K+ values.
What is a unique therapeutic use of aerosolized amiloride?
It improves muco-ciliary clearance in patients with cystic fibrosis.
What is the role of amiloride in lithium-induced nephrogenic diabetes insipidus?
It blocks Li+ transport to the cells of the collecting tubules.
What condition is Amiloride useful for treating?
Lithium-induced nephrogenic diabetes insipidus
Amiloride blocks Li+ transport to the cells of the collecting tubules.
Name two examples of mineralocorticoid antagonists.
- Spironolactone
- Eplerenone
What is the primary action of mineralocorticoids?
Cause Na+ and water retention and enhance the excretion of K+ and H+
Where are mineralocorticoid receptors (MRs) located in the nephron?
In the late distal tubule and collecting duct
What hormone is produced in the adrenal cortex that binds to mineralocorticoid receptors?
Aldosterone
What happens when aldosterone binds to mineralocorticoid receptors?
The MR-aldosterone complex translocates to the nucleus and regulates gene expression
What do aldosterone-induced proteins (AIPs) enhance?
- Na+ conductance of the luminal membrane
- Sodium pump activity of the basolateral membrane
