Diuretics Flashcards
What is a diuretic?
A drug that increases renal excretion of water and sodium
How are diuretics classified?
Loop diuretics Thiazide diuretics K+ sparing diuretics Carbonic anhydrase inhibitor Osmotic diuretic
What is the action of loop diuretics?
Inhibit Na-K-2Cl symport in thick ascending limb of LOH
What are some examples of loop diuretics?
Furosemide
Bumetanide
What is the action of thiazide diuretics?
Inhibit NaCl symport in DCT
What are some examples of thiazide diuretics?
Bundroflumethiazide
Metolazone
What are the types of potassium sparing diuretics?
ENaC inhibitors
Aldosterone antagonists
What are some examples of ENaC inhibitors?
Amiloride
Triamterene
What are some examples of aldosterone antagonists?
Spironolactone
Eplerenone
What is the action of carbonic anhydrase inhibitors?
Inhibit carbonic anhydrase in PCT
What is an example of a carbonic anhydrase inhibitor?
Acetazolamide
What is an example of an osmotic diuretic?
Mannitol
How do loop diuretics cause diuresis?
Inhibit Na-K-2Cl symport in thick ascending limb of LOH
Reduces medullary tonicity
Less water reabsorbed down stream
When are loop diuretics used?
Heart failure
Nephrotic syndrome
Renal failure
How do thiazide diuretics cause diuresis?
Inhibit NaCl symport in early DCT
Increases sodium and water loss
When are thiazide diuretics used?
Hypertension
How do ENaC inhibitors cause diuresis?
Block ENaC
Sodium not reabsorbed - more sodium and water loss in urine
How do aldosterone antagonists cause diuresis?
Reduce ENaC activity
When are aldosterone antagonists used?
Heart failure
Ascites
Cirrhosis oedema
Conn’s hypertension
How do carbonic anhydrase inhibitors cause diuresis?
Inhibit action of carbonic anhydrase in PCT
Promotes conversion of H2CO3 to water
More water loss
How do osmotic diuretics cause diuresis?
Small inert molecules that increase plasma osmolarity
Draw fluid from tissues
Increases osmolarity of filtrate in the kidney
More water, sodium and potassium loss
