Diuretics

Question 1

Acetazolamide

Answer 1

• non-competitive inhibition of carbonic anhydrase in proximal tubule
• result in increased HCO3-, H+, and K+ excretion, producing natriuresis with hyperchloremic metabolic acidosis

Question 2

Indications to use acetazolamide

Answer 2

• Glaucoma (decrease aqueous humor formation and intraocular pressure)
• facilitates excretion of acidic toxicants
• dissolves some types of urinary crystals

Question 3

Furosemide

Answer 3

• inhibits Na/K/Cl cotransport in thick ascending limb of Henle’s loop
• results in disruption of renal counter-current exchange mechanism, which concentrates urine

Question 4

Indications to use furosemide

Answer 4

• acute pulmonary edema
• acute renal failure
• accelerate excretion of toxicants
• hyperkalemia
• hypercalcemia
• hyperthryoidism

(used in racehorses to reduce exercise-induced pulmonary hemorrhage)

Question 5

Hydrochlorothiazide

Answer 5

• blocks NCC transporter in early distal tubule
• results in decreased NaCl reabsorption
• long-term result of Ca2+ reabsorption

Question 6

Spironolactone

Answer 6

• antagonist of mineralocorticoid receptors
• inhibits aldosterone-mediated induction of epithelial Na+ channels
• results in decreased distal Na+ reabsorption and decreased K+ secretion

Question 7

Indications to use spironolactone

Answer 7

• hypokalemia produced by prolonged thiazide or loop diuretic therapy or states of excess mineralocorticoid activity
• edematous conditions secondary to hyperaldosteronism

Question 8

Triamterene

Answer 8

• directly blocks epithelial Na+ channels in principle cells of late distal tubule and collecting duct
• results in decreased Na+ reabsorption and decreased K+ secretion

Question 9

Indications to use triamterene

Answer 9

• hypokalemia produced by prolonged thiazide or loop diuretic therapy or states of excess mineralocorticoid activity
• edematous conditions secondary to hyperaldosteronism

Question 10

Mannitol

Answer 10

• disrupts renal counter-current exchange in loop of Henle

- results in increased water excretion along with mild increased Na+ excretion

Question 11

Indications to use mannitol

Answer 11

• acute renal failure
• toxicant elimination
• cerebral edema
• glaucoma