21-31 - Diuretics

Question 1

carbonic anhydrase inhibitor

Answer 1

acetazolamide

Question 2

MOA acetazolamide

Answer 2

carbonic anhydrase inhibitor

decreases PCT reabsorption of HCO3-

also decreases formation of HCO3- and inhibits NH4+ secretion

Question 3

end physiological actions of acetazolamide

Answer 3

decrease RBF and GFR

diuresis

increased K excretion

** metabolic acidosis

Question 4

clinical indications for acetazolamide

Answer 4

• glaucoma
• acute mountain sickness
• induce urinary alkalinization
• edema (combine with NKCC or NCC inhibitor)

Question 5

is carbonic anhydrase located only in the renal system?

Answer 5

no

also in ciliary body, kidney, erythrocytes, gut, choroid plexus, and glial cells

Question 6

adverse effects of acetazolamide

Answer 6

• hyperchloremic metabolic acidosis
• renal stones
• renal loss of K+

Question 7

contraindication for acetazolamide

Answer 7

cirrhosis

because increases plasma NH4+

Question 8

osmotic diuretic example

Answer 8

mannitol

Question 9

MOA mannitol

Answer 9

osmotic diuretic

Question 10

MOA osmotic diuretics

Answer 10

increase tubular fluid osmotic pressure and thereby decrease water reabsorption

Question 11

most potent diuretics

Answer 11

loop agents

Question 12

indications for mannitol

Answer 12

• phophylaxis of acute renal failure
• cerebral edema
• dialysis disequilibrium syndrome
• acute attacks of glaucoma

Question 13

why can osmotic diuretics be used for prophlylaxis of acute renal fialure?

Answer 13

expands the ECV, maintains the GFR, increases tubular fluid flow, prevent tubule obstruction from shed cell
reduces renal edema

Question 14

adverse effects of osmotic diuretics

Answer 14

risk of pulmonary edema in pts with heart failure

hyponatremia or hypernatremia depending on speed of fluid loss

Question 15

contraindications for mannitol

Answer 15

anuria due to real disease

impaired liver function

active cranial bleeding

Question 16

NKCC inhibitor

Answer 16

aka loop diuretics

ex: furosemide

Question 17

furosemide clasification

Answer 17

loop diuretic aka NKCC inhbitor

Question 18

MOA furosemide

Answer 18

inhibits NKCC cotransporter –> inhibit reabsorption of solute

also venodilation (decreased RA pressue and pulmonary capillary wedge pressure)

Question 19

what happens to calcium and magnesium with loop diuretics?

Answer 19

increases calcium excretion 30% (gradient potential change)

increases Mg excretion by 60% (b/c voltage dependent)

Question 20

indications for loop diuretics

Answer 20

• pulmonary edema
• CHF
• acute renal failure
• hypercalcemia

Question 21

major adverse effect of furosemide

Answer 21

hypokalemia

Question 22

MOA NCC inhibitors

Answer 22

block NaCl cotransporter and decrease calcium excretion

Question 23

chlorthalidone classification

Answer 23

NCC inhibitor

Question 24

indications for chlorthalidone

Answer 24

HTN
edema with CHF
hypercalciuria
nephrolithiasis
Nephrogenic diabetes insipidus

Question 25

NCC inhibitors aka

Answer 25

thiazides and sulfonamides

Question 26

how does chlorthalidone treat nephrogenic diabetes insipidus?

Answer 26

increases renal sodium reabsorption

recovers aquaporin2 abundance

Question 27

inhibitor of renal epithelial sodium channels

Answer 27

amiloride

Question 28

MOA amiloride

Answer 28

block epithelial sodium channels on prinicpal cells in late DCT and initial connecting tubule and cotical collecting ducts –> omdest natriuresis and prevention of K loss

Question 29

indications for amiloride

Answer 29

• hypokalemic alkalosis

- combo with loop diuretics and thiazides to prevent hypokalemia

Question 30

aldosterone receptor agonist

Answer 30

spironolactone

Question 31

MOA spironolactone

Answer 31

antagonize aldosterone receptos in renal collecting tubules

decreas sodium reabsorption –> K sparing diuretic

Question 32

pleiotropic effects of spironolactone

Answer 32

• prevention of LV remodeling and cardiac fibrosis
• prevention of sudden cardiac death
• hemodynamic effects
• vascular effects

Question 33

indications for spironolactone

Answer 33

• edema and HTN
• added to therapy for HF
• primary aldosteronism
• refractory edema associated with secondary aldosteronism

Question 34

what is refractory edema with seconday aldosteronism?

Answer 34

CF, hepatc cirrhosis, nephrotic syndrome, and severe ascites all make the body think it doesn’t have enough water –> increased aldosterone secretion

treat with spioronolactone

Question 35

adverse effect of spironolactone

Answer 35

hyperkalemia

other adverse effects include metabolic acidosis in cirrhotic pts, and effects due to binding to other steroid receptors including gynecomastia, hirsutism, deepened voice, etc.