Lecture 21: Diuretics

Question 1

where do loop diuretics act

Answer 1

Thick ascending loop of henle on the NKCC2 transporter

Question 2

The thick ascending loop of henle is impermeable to ___

Answer 2

Water

Question 3

What ions are reabsorbed in thick ascending LOH

Answer 3

Na+, Cl-, K+, Mg2+, and Ca2+

Question 4

What type of diuretic is furosemide

Answer 4

Loop diuretic

Question 5

What are the pharmacodynamics of furosemide

Answer 5

Acts on thick ascending LOH, inhibits NKCC and reduces Na+ reabsorption

Question 6

Loop diuretics increase the excretion of __ and ___

Answer 6

Mg2+ and Ca2+

Question 7

Loop diuretics cause __kalemia and what does it do to pH

Answer 7

Hypokalemia, and alkalosis

Question 8

How do loop diuretics cause hypokalemia

Answer 8

Na+ load is greater at CD and therefore the exchange between Na+ reabsorption and K+ loss is greater

Question 9

Loop diuretics cause __kalemia __chloremic alkalosis

Answer 9

Hypokalemia hypochloremic alkalosis

Question 10

Loop diuretics induce synthesis of __ which causes vasodilation

Answer 10

Prostaglandin

Question 11

What do loop diuretics primarily relieve and how

Answer 11

Pulmonary congestion by increasing systemic venous capacitance/vasodilating via PG synthesis

Question 12

What species is furosemide labeled for

Answer 12

Dogs, cats, horses and cattle

Question 13

Furosemide is the drug of choice for ___

Answer 13

Rapid mobilization of edema fluid

Question 14

Furosemide increases Ca2+ excretion and therefore is used in the treatment of __ and ___ in dogs and cats

Answer 14

Hypercalcemia and hypercalciuric nephropathy in dogs and cats

Question 15

What does furosemide prevent in race horses and how

Answer 15

Exercise induced pulmonary hemorrhage and epitaxis via vasodilatory effects of PG synthesis

Question 16

What are some furosemide related toxicity symptoms

Answer 16

1. Abnormalities in fluid and electrolytes
2. hypokalemia
3. hypocalcemia
4. hypomagnesemia
5. hyperuricemia
6. hypovolemia
7. hyponatremia

Question 17

hypokalemia induced furosemide diuresis potentiates ___ toxicity

Answer 17

digoxin

Question 18

What type of diuretic is hydrochlorothiazide

Answer 18

Thiazide diuretic

Question 19

Where do thiazide diuretics act

Answer 19

NCC transporter in ascending limb of DCT

Question 20

What is the mechanism of action of thiazide diuretics

Answer 20

Inhibit Na+ reabsorption at cortical diluting site

Question 21

Thiazide diuretic effects are dependent on ___ synthesis and may be inhibited by ___

Answer 21

PG, NSAIDS

Question 22

Thiazide diuretics are a stimulus for aldosterone which causes ___

Answer 22

Hypokalemia

Question 23

Thiazide diuretics cause a decrease in ___ excretion

Answer 23

Ca2+

Question 24

What are some toxicity signs from thiazide diuretics

Answer 24

Hypokalemia metabolic alkalosis, hyperuricemia, hypercalemia

Question 25

What are thiazide diuretics commonly used for

Answer 25

1. Quarter horses with hyperkalemic periodic paralysis 2. Long term treatment for dogs and cats in HF (furosemide is DOC) 3. Prevention of calcium oxalate uroliths

Question 26

What drug is FDA approved for use in dairy cattle for treatment of post partum udder edema (labeled product d/c in US)

Answer 26

Chlorothiazide

Question 27

Where do potassium sparing diuretics act

Answer 27

Cortical collecting tubule

Question 28

What type of diuretic is spirnolactone

Answer 28

Potassium sparing

Question 29

How does spironolactone work

Answer 29

Competitive inhibitor of aldosterone, promotes Na+ excretion and inhibits K+ excretion

Question 30

When is spironolactone used

Answer 30

CHF that is unresponsive to furosemide, hepatic cirrhosis, nephrotic syndrome, and severe ascites

Question 31

Caution should be taken when use spironolactone with __ inhibitors. Why?

Answer 31

ACE inhibitors, because both block aldosterone and can result in hyperkalemia

Question 32

How is mannitol administered

Answer 32

IV only, not absorbed orally- will produce diarrhea

Question 33

When is mannitol used

Answer 33

1.prophylaxis acute renal failure 2. Reduce IOP 3. Reduce ICP 4. Protect kidney against nephrotoxic substances

Question 34

Mannitol may produce ___in HF patients

Answer 34

Pulmonary edema

Question 35

Where do carbonic anhydrase inhibitors act

Answer 35

proximal tubule

Question 36

What class of drug is acetazolamide

Answer 36

Carbonic anhydrase inhibitor

Question 37

What is the mechanism of action of acetazolamide

Answer 37

Inhibit CA enzyme and block HCO3- reabsorption, reduces Na+ reabsorption and increases Na+/K+ exchange

Question 38

What is acetazolamide used for

Answer 38

1. Reducing aqueous humor production in glaucoma patients 2. Hyperkalemic periodic paralysis in quarter horses

Question 39

When is acetazolamide contraindicated

Answer 39

Hepatic cirrhosis (decreases ammonia excretion)

Question 40

What is the blood pH of patient on loop diuretics

Answer 40

Alkalosis

Question 41

What is the blood pH of patient on thiazide diuretics

Answer 41

Alkalosis

Question 42

What is the blood pH of patient on potassium sparing diuretics

Answer 42

Acidosis

Question 43

What is blood pH of patient on carbonic anhydrase inhibitors

Answer 43

Acidosis