Lecture 21: Diuretics Flashcards

1
Q

where do loop diuretics act

A

Thick ascending loop of henle on the NKCC2 transporter

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2
Q

The thick ascending loop of henle is impermeable to ___

A

Water

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3
Q

What ions are reabsorbed in thick ascending LOH

A

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

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4
Q

What type of diuretic is furosemide

A

Loop diuretic

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5
Q

What are the pharmacodynamics of furosemide

A

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

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6
Q

Loop diuretics increase the excretion of __ and ___

A

Mg2+ and Ca2+

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7
Q

Loop diuretics cause __kalemia and what does it do to pH

A

Hypokalemia, and alkalosis

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8
Q

How do loop diuretics cause hypokalemia

A

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

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9
Q

Loop diuretics cause __kalemia __chloremic alkalosis

A

Hypokalemia hypochloremic alkalosis

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10
Q

Loop diuretics induce synthesis of __ which causes vasodilation

A

Prostaglandin

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11
Q

What do loop diuretics primarily relieve and how

A

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

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12
Q

What species is furosemide labeled for

A

Dogs, cats, horses and cattle

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13
Q

Furosemide is the drug of choice for ___

A

Rapid mobilization of edema fluid

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14
Q

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

A

Hypercalcemia and hypercalciuric nephropathy in dogs and cats

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15
Q

What does furosemide prevent in race horses and how

A

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

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16
Q

What are some furosemide related toxicity symptoms

A
  1. Abnormalities in fluid and electrolytes
  2. hypokalemia
  3. hypocalcemia
  4. hypomagnesemia
  5. hyperuricemia
  6. hypovolemia
  7. hyponatremia
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17
Q

hypokalemia induced furosemide diuresis potentiates ___ toxicity

A

digoxin

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18
Q

What type of diuretic is hydrochlorothiazide

A

Thiazide diuretic

19
Q

Where do thiazide diuretics act

A

NCC transporter in ascending limb of DCT

20
Q

What is the mechanism of action of thiazide diuretics

A

Inhibit Na+ reabsorption at cortical diluting site

21
Q

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

A

PG, NSAIDS

22
Q

Thiazide diuretics are a stimulus for aldosterone which causes ___

A

Hypokalemia

23
Q

Thiazide diuretics cause a decrease in ___ excretion

A

Ca2+

24
Q

What are some toxicity signs from thiazide diuretics

A

Hypokalemia metabolic alkalosis, hyperuricemia, hypercalemia

25
Q

What are thiazide diuretics commonly used for

A
  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
26
Q

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

A

Chlorothiazide

27
Q

Where do potassium sparing diuretics act

A

Cortical collecting tubule

28
Q

What type of diuretic is spirnolactone

A

Potassium sparing

29
Q

How does spironolactone work

A

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

30
Q

When is spironolactone used

A

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

31
Q

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

A

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

32
Q

How is mannitol administered

A

IV only, not absorbed orally- will produce diarrhea

33
Q

When is mannitol used

A

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

34
Q

Mannitol may produce ___in HF patients

A

Pulmonary edema

35
Q

Where do carbonic anhydrase inhibitors act

A

proximal tubule

36
Q

What class of drug is acetazolamide

A

Carbonic anhydrase inhibitor

37
Q

What is the mechanism of action of acetazolamide

A

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

38
Q

What is acetazolamide used for

A
  1. Reducing aqueous humor production in glaucoma patients
  2. Hyperkalemic periodic paralysis in quarter horses
39
Q

When is acetazolamide contraindicated

A

Hepatic cirrhosis (decreases ammonia excretion)

40
Q

What is the blood pH of patient on loop diuretics

A

Alkalosis

41
Q

What is the blood pH of patient on thiazide diuretics

A

Alkalosis

42
Q

What is the blood pH of patient on potassium sparing diuretics

A

Acidosis

43
Q

What is blood pH of patient on carbonic anhydrase inhibitors

A

Acidosis