(3.2) Diuretics

Question 1

classes of K+ sparing

Answer 1

Na Channel blocker

Aldosterone antagonist

Question 2

Loop diuretics

Answer 2

K wasting

Na K 2Cl blocker in the thick ascending loop

indirectly blocks Ca reabsorption

sulfa

Question 3

furosemide class and application

Answer 3

loop diuretic

for Edema/heart failure/hepatic disease/renal disease

decrease preload and rapid dyspnea relief

treats HTN patients

WORKS REGARDLESS OF GFR AND RBF

Question 4

Furosemide kinetics and concerns

Answer 4

IV 5 min (lasts 2 hrs)
PO 30-60 min (lasts 6-8 hrs)
IM 30 min

eliminated as unchanged drug in urine

hypokalemia
hyponatremia 
hypocalcemia
hypomagnesia
hypochloremia and alkalosis

hyperglycemia
hyperuricemia
^ cholesterol and TG

ototoxicity! and is a sulfa!

Question 5

torsemide

Answer 5

loop diuretic

longer half life than furosemide

better oral absorption and works in heart failure better

Question 6

bumetanide

Answer 6

loop diuretic

with more predictable oral absorption

Question 7

ethacrynic acid

Answer 7

loop diuretic

NOT a sulfa drug

Question 8

Thiazide diuretics

Answer 8

K wasting

NaCl contransport blockers
in the DCT

‘thiazide’

Question 9

hydrochlorothiazide class and application

Answer 9

thiazide diuretic

mild-moderate hypertension

treatment of edema

off-label calcium nephrolithiasis

DOES NOT WORK WELL WITH LOW GFR

Question 10

hydrochlorothiazide kinetics/concerns

Answer 10

well absorbed orally with 65-75% availability

peak action in 2 hrs with total duration of 6-12hrs

excreted in urine unchanged

orthostatic hypotension

hypokalemia
hypomagnesemia
hyponatremia
hypochloremic metabolic alkalosis

hypercalcemia
hyperglycemia
hyperuricemia

SULFA drug

Question 11

chlorothiazide

Answer 11

thiazide diuretic like HCTZ

poor oral absorption

Question 12

chlorthalidone

Answer 12

thiazide diuretic like HCTZ

40-60 hr half life often preferred by HTN specialists

Question 13

metolazone

Answer 13

long acting thiazide diuretic that is a favourite by cardiologists

Question 14

Na channel blocker Diuretics

Answer 14

K SPARING

blocks epithelial sodium (ENaC) in the collecting ducts

small increase in Na excretion

blocks K excretion pathway

H Mg and Ca excretion decreased

Question 15

amiloride class and application

Answer 15

Na channel blocker

counteracts K loss induced by other diuretics

off label for ascites
pediatric HTN

Question 16

amiloride kinetics/concerns

Answer 16

orally <2 hour onset
half life 6-9 hrs with low GFR

excreted unchanged (50%) urine and (40%) feces

hyperkalemia 
hyponatremia
hypovolemia
hypercholermic metabolic ACIDOSIS
dizziness/fatigue/headache
nausea/vomiting/bloating/diarrhea

Question 17

triamterene

Answer 17

Na channel blocker

for edema and off label HTN

duration is 6-9 hrs eliminated as drug metabolite

Question 18

Aldosterone antagonist diuretics

Answer 18

K sparing

competitive antagonist of aldosterone receptors and partial androgen agonist

decrease Na entry through luminal Na channels and decreases Na-K ATPase on basolateral

Question 19

spironolactone class and application

Answer 19

Aldosterone antagonist

counteracts K loss induced by other diuretics

treatment for primary hyperaldosteronism

off label to reduce fibrosis in post-mi heart

hirsutism and treatment of andorgenic alopecia in females

Question 20

spironolactone kinetics/concerns

Answer 20

active metabolites including canrenone with half life of ~20 hours

steroid so slow on and off

hyperkalemia

amenorrhea/hirsutism/gynecomastia/impotence

tumorigen in chronic animal toxicity studies

Question 21

epelrenone

Answer 21

more selective aldosterone antagonist that lacks sulfur

10x more expensive but lacks side effect severity of spironolactone

Question 22

vaptans class

Answer 22

ADH antagonist

promotes excretion of free water

helps restore normal plasma Na conc

Question 23

conivaptan class and application

Answer 23

vaptan V1 and V2

euvolemic and hypervolemic hyponatremia in pts who are

hospitalized/symptomatic/non-responsive to fluid restriction

need close monitoring

Question 24

conivaptan kinetics/concerns

Answer 24

IV administration

CYP3A4 substrate

water loss can concentrate other electrolytes

eliminated primarily in feces as metabolite

orthostatic hypotension/fatigue/thirst/bed wetting and polyuria

Question 25

tolvaptan

Answer 25

ADH receptor antagonist V2 specifically

orally

only used in hospital

must use < 30 days for hyponatremia any more can be hepatotoxic

Question 26

licorice

Answer 26

glycyrrhizic acid

potentiates aldosterone effects in kidney and dose dependent increase BP 3-14 mmHg

Question 27

example of herbal diuretics

Answer 27

chicory, dandelion leaves, fennel, golden seal, hops, marshmallow, stinging nettle, parsley, saffron, sage, sassafras, saw palmetto berries, skullcap, spearmint, St. John’s wort, strawberry leaves, uva-ursi, wintergreen and yarrow

Question 28

carbonic anhydrase inhibitors

Answer 28

work in proximal tubule

made from sulfanilamide

inhibits Na/H exchange

causes hypercholermic acidosis

Question 29

Azetazolamide/dorzalamide

Answer 29

carbonic anhydrase inhibitor

urinary alkalization

used for mountain sickness and glaucoma and metabolic alkalosis

causes metabolic acidosis, renal stones, and K+ wasting

Question 30

mannitol

Answer 30

osmotic diuretic

works through oncotic pressure in the proximal tubule

ECV is increased and can increase HF

headache, nausae, vomiting, fluid, and electroly inbalance

Question 31

mannitol therapeutic uses

Answer 31

prophylaxis of renal failure, keeps some fluid volume in the tubules to prevent them from collapsing when the glomerular filtration rate is very low

reduction of intracranial pressure

reduction of intraocular pressure (treating glaucoma) when patients haven’t responded to other therapy