7 - Diuretics Flashcards Preview

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Flashcards in 7 - Diuretics Deck (19):
1

acetazolamide - mech

inhibit carbonic anhydrase in PCT
inc NaBicarb diuresis
can cause hyperchloremic metab acidosis

2

clinical uses of acetazolamide

glaucoma
urinary alkalinization (inc solubility of uric acid and cysteine)
metab alkalosis (diuretic induced)
acute mountain sickness

3

acetazolamide AEs

hyperchloremic metab acidosis
hypokalemia

4

how do most diuretics cause renal K wasting?

inc distal Na delivery drives K secretion (Na-K exchangers that aldosterone works on)

5

how do osmotic diuretics work?

prevent water reabs in PCT and dLoH
oppose ADH action in CD
inc urine flow rate > dec contact time btwn fluid and tubular epithelium > reduce Na reabs > diuresis

6

uses of osmotic diuretics (eg mannitol)

cerebral edema
acute congestive glaucoma
prevent oliguric phase in AKI (ex hemolysis, rhabdomyolysis)

7

osmotic diuretic AEs

EC volume expansion + hyponatremia
dehydration + hypernatremia

8

loop diuretic mechanism

inhibit Na/K/2Cl transporter in TAL of Loop
very potent - induces NaCl diuresis
inc Mg and Ca excretion b/c dec luminal positive potential
K wasting
induce renal PG synth > inc RBF and vasodilation

9

uses of loop diuretics

pulm edema
edematous conditions (heart failure, cirrhosis, nephrotic syndrome)
HTN - refractory, assoc w/ renal insuff or HF, HTN emergency
hypercalcemia and hyperkalemia
SIADH

10

how does furosemide work to counter SIADH?

block Na reabs in loop of henle >
abolish hyperosmolarity of medulla >
hinder Na reabs due to ADH in distal nephron

11

loop diuretics AEs

hypokalemic metab alkalosis
hypomagnesemia
hyperuricemia
ototoxicity (dose related)

12

thiazide diuretics mechanism

block Na/Cl cotransporter in DCT
induce NaCl diuresis
inc Ca reabsorption
renal K wasting

13

uses of thiazides

HTN
heart failure
renal stones due to idiopathic hypercalciuria
nephrogenic DI

14

how do thiazides work in nephrogenic DI?

thiazide induced Na loss stimulates Na reabs in PCT > dec urine formation over time

15

thiazides AEs

hypokalemic metab acidosis
hyperuricemia
hyponatremia
hyperglycemia
hyperlipidemia

16

mechanisms of both types of K sparing diuretics

spironolactone/eplerenone - direct antagonism of MR receptors (aldosterone)

amiloride/triamterene - inhibition of Na entry through ion channels in luminal membrane

both increase urine NaCl excretion
can cause hyperkalemia / metabolic acidosis

17

K sparing diuretic use

primary and secondary hyperaldosteronism
heart failure
cirrhosis

18

K sparing diuretic AEs

hyperkalemia
hyperchloremic metab acidosis (like type IV RTA)
gynecomastia (specifically spironolactone)

19

approaches to diuretic resistance

make sure they are following salt restriction + med intake
discontinue NSAIDs
adjust dose of diuretic if renal impairment - protein bound diuretic gets wasted in albuminuria
switch to IV admin if absorption is a concern
continuous IV infusion for loop diuretic to avoid postdiuretic salt retention
combine loop diuretics w/ other diuretics (preferably thiazide)