Diuretics

Question 1

diuretics as tx for the big 3

Answer 1

edema
HTN
heart failure

Question 2

diuretic definition

Answer 2

a substance that increases the volume of urine

“increase excretion of sodium along with water”

Question 3

mechanism of increased Na excretion

Answer 3

inhibition of Na reabsorption

NOT increasing glomerular filtration

Question 4

which is absorbed better? furosemide or bumetanide?

Answer 4

bumetanide (and more potent)

Question 5

Furosemide MOA

Answer 5

inhibit Na/Cl absorption at the TAL, K+ leaks back out into lumen

Question 6

what two ions are lost with loop diuretics?

Answer 6

calcium/magnesium (usually absorbed across the TAL due to charge gradient)

Question 7

urine osmolality on loop diuretics?

Answer 7

close to that of plasma - cannot maintain medullary conc gradient and thus cannot conc urine

Question 8

how do loops initially relieve CHF sx?

Answer 8

via dilation of veins (prostaglandins?)

Question 9

what drug blunts dilation and diuresis action of loops?

Answer 9

NSAIDS

Question 10

what happens to starling forces on a loop?

Answer 10

hydrostatic down, oncotic up

Question 11

after weeks of antidiuretic therapy?

Answer 11

intravascular volume is restored, but blood pressure remains low (as long as salt intake is not increased)

Question 12

Loop SE’s that make sense

Answer 12

Volume depletion –> postural hypotension
Urination (sleep)
Depletion of total body sodium
Low serum K+ (most common SE) –> cramps/weakness
and arrhythmias
Hypokalemic alkalosis (H+ follows K+)
Mg/Ca depletion
Threaten blood flow to fetus (NOT used for P-E)

Question 13

Loop SE’s that don’t make sense

Answer 13

Increased uric acid, glucose, cholesterol
Gout, worsen diabetes, increase coronary risk
Reversible deafness –> endolymph upset
Allergic rxns –> sunburn (SULFA)
Pancreatitis
Hepatorenal syndrome (DO NOT Tx PTS WITH LIVER FAILURE WITH FUROSEMIDE!!!)

Question 14

Drug to NOT rx to pts with liver failure

Answer 14

Furosemide

Question 15

Defect in Na/CL cotransporter

Answer 15

Giterman’s syndrome

Question 16

why are thiazides helpful in osteoporosis?

Answer 16

cause retention of calcium

same prostaglandin effects as loops

Question 17

thiazides for acute heart failure?

Answer 17

no, weaker and take longer to work than loops

Question 18

most common use for thiazides

Answer 18

HTN
eventually reduction in TPR (prostaglandins?)
reduction in activity to pressors?

Question 19

thiazide SE’s that can be explained

Answer 19

postural hypotention
extreme sodium depletion
increased K+ excretion
hypokalemic alkalosis (H+ excreted at the site where aldosterone works)
hypomagnesemia (tremors/twitches/arrhythmias/nausea)

Question 20

thiazide SE’s that can not be explained

Answer 20

inhibit uric acid excretion --> gout
decreased glucose tolerance
inhibit insulin release
hyperlipidemia
reduce excretion of calcium (opposite to loops)
pancreatitis
sulfa allergy (sunburns)
hepatorenal syndrome
impotence

Question 21

thiazide duration of action

Answer 21

longer than loops

SO if crit > 2.0, use loops instead so to not prolong aggravation of renal failure

Question 22

K-sparing site of action

Answer 22

collecting duct
small diuretic effect
large K-sparing effect

Question 23

Sprio/eplereno MOA

Answer 23

competitively inhibit aldosterone

lower K/Mg/H+ excretion

Question 24

when are K-sparers only effective?

Answer 24

when adrenal is making aldo

Question 25

Spiro/eplereno SE's

Answer 25

``` *hyperkalemia (ACE-i's can predispose to this) gynecomastia, menstrual irregs anti-androgenic --> inc estrogen levels nausea, GI sx ```

Question 26

triamter/amilo MOA

Answer 26

inhibit the Na/K exchange site (ENaC) | work regardless if aldo is present

Question 27

Liddle's syndrome

Answer 27

ENaC channel always on

Question 28

Tx for Liddle's syndrome?

Answer 28

Amiloride

Question 29

Tri/Amilo SE's

Answer 29

hyperkalemia (most worrisome b/c asymptomatic) | exaggerated on ACE-i's

Question 30

other effects of all K-sparers

Answer 30

magnesium-sparing | NO change in blood levels of uric acide/glucose/lipids

Question 31

used to reduce edema in brain or eye

Answer 31

mannitol

Question 32

effects common to all diuretics

Answer 32

initial volume depletion rise in plasma renin/aldo Na loss Mg/K loss except K-sparers

Question 33

calcium effects: loop v. thiazide

Answer 33

loop --> loss | thiazide --> spare

Question 34

Lithium: furosemide v. thiazides

Answer 34

furosemide: no change thiazides: reduce excretion of lithium * decrease dose by 1/3 when adding a diuretic

Question 35

NSAIDS do what to diuretics?

Answer 35

reduce anti-HTN effects

Question 36

Digitalis

Answer 36

increased arrhythmias while on diuretics

Question 37

loop diuretics interact how with antibiotics?

Answer 37

increase toxic effects on ear/kidney

Question 38

amphotericin B with diuretics causes what

Answer 38

increased K+ loss

Question 39

Thiazides do what to glucose levels?

Answer 39

elevate