Exam 4: Diuretics

Question 1

Prototype thiazide diuretic:

Answer 1

Hydrochlorothiazide

Question 2

Site of action of thiazides:

Answer 2

Distal convoluted tubule

Question 3

MoA of thiazides:

Answer 3

Impairs Na+/Cl+ reabsorption, drawing water into the filtrate to be excreted

Question 4

Precaution with thiazides:

Answer 4

K+ depleting

Question 5

HTN mechanism of thiazides:

Answer 5

Peripheral vasodilation

Question 6

Anesthesia concerns with thiazides:

Answer 6

Electrolytes: hypokalemia, hypochloremia, hypomagnesemia
Muscle weakness that potentiates NMBs
Nephropathy
Increased risk of dig toxicity
Fluid volume depletion

Question 7

Dose effects of thiazides:

Answer 7

Increased dose has little extra effect

Question 8

Prototype loop diuretic:

Answer 8

Furosemide

Question 9

Site of action of loop diuretics:

Answer 9

Thick ascending loop of Henle

Question 10

MoA of furosemide:

Answer 10

Inhibit the passive transport of K+/Na+/Cl- from the lumen, keeping them + water in the filtrate

Question 11

PK of furosemide:

Answer 11

Onset: 2 - 10min (IV)
Extensively protein bound
Renal secretion!

Question 12

Indications for furosemide:

Answer 12

Mobilization of edema
Reduction of ICP
Hypercalcemia
Differential dx of oliguria

Question 13

Dosage of furosemide:

Answer 13

0.1 - 1.0 mg/kg (titrate)

Question 14

Electrolyte changes with loop diuretics:

Answer 14

Hypokalemia

Hypochloremia

Question 15

A/E of loop diuretics:

Answer 15

Potentiation of NMBs

Presynaptic cAMP inhibition, ACh release

Question 16

Drug interactions with loop diuretics:

Answer 16

Nephrotoxicity when administered with aminoglycosides and cephalosporins

Possible cross reactivity to sulfonamide allergy

Decreases renal clearance of lithium

Question 17

Prototype drug for osmotic diuretics:

Answer 17

Mannitol

Question 18

Site of action of osmotic diuretics:

Answer 18

Tubules

Question 19

MoA of osmotic diuretics:

Answer 19

Increased osmolarity in tubule → Na+, Cl-, HCO3- excreted along with water

Question 20

Concern with osmotic diuretics:

Answer 20

Increases plasma osmolarity and intravascular volume; can cause pulmonary edema in poor LV function

Question 21

PK of osmotic diuretics:

Answer 21

Do not enter cells; must be given IV
Onset: 10 - 15min
Duration: 2 hrs
100% renally excreted

Question 22

Indications for mannitol:

Answer 22

Differential dx of oliguria (after furosemide)
Prophylaxis for ARF
↓ ICP
↓ IOP

Question 23

Dose of mannitol:

Answer 23

0.25 - 1 g/kg IV

Question 24

Anesthesia concerns with mannitol:

Answer 24

Pulmonary edema
Hypovolemia
Electrolyte changes

Question 25

Two classes of potassium sparing diuretics:

Answer 25

Epithelial Na+ channel blockers

Aldosterone antagonists

Question 26

Prototype epithelial Na+ channel blocker:

Answer 26

Triamterene

Question 27

Site of action of triamterene:

Answer 27

Collecting duct

Question 28

MoA of triamterene:

Answer 28

Na+ channel blockade in the luminal membrane; non-competitive antagonism of aldosterone

Question 29

A/E of triamterene:

Answer 29

Can cause hypERkalemia

Question 30

Prototype aldosterone antagonist:

Answer 30

Spironolactone

Question 31

MoA of spironolactone:

Answer 31

Competitive aldosterone antagonist; weak and usually combined with other diuretics

Question 32

Indications for spironolactone:

Answer 32

HF
Ascites
Low-renin hypertension
Hypokalemia
Conn's syndrome

Question 33

Prototype carbonic anhydrase inhibitor:

Answer 33

Acetazolamide

Question 34

MoA of acetazolamide:

Answer 34

Blocks the action of carbonic anhydrase, increasing HCO3-, Na+, and H2O in urine

Question 35

Indications for acetazolamide:

Answer 35

Glaucoma
Altitude sickness
ICP