Renal

Question 1

main function of loop of Henle

Answer 1

concentrate the urine

Question 2

3 general reasons to use diuretics

Answer 2

mobilize tissue fluid; reduce blood volume; protect kidney function

Question 3

5 major classes diuretics

Answer 3

carbonic anhydrase inhibitors; osmotic diuretics; loop diuretics; thiazide diuretics; potassium sparing diuretics

Question 4

goal of diuretic use

Answer 4

increase excretion of sodium followed by water

Question 5

what class of diuretics are non-competitive, reversible inhibitors of carbonic anhydrase and primarily used for glaucoma management by reducing the production of aqueous humour

Answer 5

carbonic anhydrase inhibitors

Question 6

why do carbonic anhydrase inhibitors have self limiting diuretic effects

Answer 6

systemic acidosis makes H+ available in the cell again (less H+ available in proximal tubular cell to exchange for sodium, more sodium remains in lumen and forms sodium bicarb, more bicarb excreted in tubular fluid, systemic acidosis occurs, H+ becomes available again in tubular cells)

Question 7

this systemic carbonic anhydrase inhibitor is used for acute treatment of glaucoma in dogs, preventative for HYPP in horses, and has self-limiting diuretic effects

Answer 7

acetazolamide

Question 8

why should you use topical rather than systemic carbonic anhydrase inhibitors in cats

Answer 8

cats are more susceptible to adverse effects of systemic CAIs. topical CAIs tend not to cause adverse systemic effects

Question 9

this topical carbonic anhydrase inhibitor can be used to treat glaucoma in dogs and cats (first line treatment in cats)

Answer 9

dorzolamide

Question 10

all diuretics except for this class inhibit specific targets that play a role in renal tubular sodium reabsorption

Answer 10

osmotic diuretics

Question 11

all diuretics except spironolactone are inside the tubular lumen. where do they need to reach adequate concentration in to be effective?

Answer 11

urine

Question 12

what is the primary mechanism of action of carbonic anhydrase inhibitors?

Answer 12

interact with enzymes

Question 13

what is the primary mechanism of action of osmotic diuretics

Answer 13

osmotic effects in water permeable regions of nephron

Question 14

what is the primary mechanism of action of both loop diuretics and thiazide diuretics?

Answer 14

interact with specific membrane transport proteins

Question 15

what is the primary mechanism of action of potassium-sparing diuretics?

Answer 15

interact with hormone receptors

Question 16

this osmotic diuretic increases the osmolarity of fluid within the nephron to be closer to that of interstitial fluid, reducing passive diffusion of water outside of the nephron. it is an inert substance that is mostly not metabolized.

Answer 16

mannitol

Question 17

what are 3 pharmacodynamic properties of mannitol (hint: relate to blood)

Answer 17

increased cardiac output, decreased rigidity of RBC membranes (enhanced blood flow), reduced hematocrit

Question 18

name at least 1 main therapeutic indication for mannitol

Answer 18

increased intracranial pressure; renal failure

Question 19

name at least 1 adverse effect of mannitol

Answer 19

hypertonic dehydration; cardiac arrhythmias; acute hyponatremia after rapid admin, volume overload in oliguric patients, CHF or pulmonary edema in risk patients, hyperosmolar state

Question 20

this is the most commonly used diuretic in vet med. what is it, what class of diuretic is it, and what is your goal with its use?

Answer 20

furosemide; loop diuretic; use lowest effective dose

Question 21

name at least 2 adverse effects of furosemide

Answer 21

volume depletion and hyponatremia; electrolyte abnormalities, cardiac effects, renal effects; (also mentioned, ototoxicity in cats, hyperglycemia)

Question 22

this potassium-wasting loop diuretic has a rapid onset, short duration of action, and kidney is major site of action, metabolism, and excretion. what is this drug and what are 2 of its hemodynamic effects?

Answer 22

furosemide; increase venous compliance, decreased pulmonary artery pressure, increased renal blood flow and GFR

Question 23

furosemide has many drug interactions. if you give it concurrently with ACE inhibitors, what should you do?

Answer 23

reduce furosemide dose

Question 24

this diuretic class is extensively protein bound, so are not filtered at the glomerulus and gain access to lumen of tubules via proximal tubular secretion

Answer 24

thiazide diuretics

Question 25

why do thiazide diuretics increase arrhythmia risk

Answer 25

potassium-wasting

Question 26

what are two potassium-sparing diuretics (avoid loss of potassium seen with other diuretics)?

Answer 26

mineralocorticoid receptor antagonists (eg. spironolactone); epithelial sodium channel blockers (eg. amiloride, triamterene)

Question 27

this potassium-sparing diuretic acts in the late distal tubule and collecting duct to block binding of aldosterone to its receptor, preventing it from initiation transcription of genes affecting sodium reabsorption, and is often administered with a thiazide or loop diuretic to increase diuresis.

Answer 27

spironolactone

Question 28

spironolactone is linked to liver disease. how would you treat secondary hyperaldosteronism with increased sodium and water retention?

Answer 28

aldosterone antagonist

Question 29

why should you use potassium-sparing diuretics cautiously with ACRE inhibitors?

Answer 29

to avoid hyperkalemia, an adverse effect of potassium-paring diuretics

Question 30

the renal medulla has low blood flow but high oxygen demand, so exists on the verge of hypoxia. what is the effect of diuretics that decrease sodium reabsorption?

Answer 30

decrease renal oxygen demand and increase renal oxygenation (especially in the thick ascending limb of loop of Henle)