diuretics 2

Question 1

loop diuretics are associated with

Answer 1

increase in Mg++, Ca++ excretion

diminish lumen-positive potential

Question 2

loop diuretics act on

Answer 2

Increase renal blood flow via effect on renin-angiotensin and prostaglandin systems

Question 3

Loop diuretic absorption is handled by

Answer 3

1. glomerular filtration

2. renal secretion

Question 4

loop diuretics have the same organic acid transporter as

Answer 4

uric acid

mechanism for hyperuricemia

Question 5

loop diuretics used in pt with

Answer 5

HF with volume overload to eliminate symptoms of fluid retention

Question 6

furosemide is most commonly used if lack of response:

Answer 6

1. Increase initial dose of furosemide
2. Switch to bumetanide or torsemide –> more reliable bioavailability and longer duration of action
3. IV administration may be required initially due to congestion-related interference with oral absorption
4. Ethacrynic acid can be used if sulfa allergy

Question 7

Patients with HF have reduced

Answer 7

diuretic response

1. Decreased drug delivery to kidney via decreased RBF
2. Hypoperfusion activates RAAS and SNS

Question 8

Thiazide added functions to

Answer 8

block distal tubule Na+ reabsorption –> counter loop-induced increases in Na+ delivery

Question 9

aldosterone antagonist in refractory edema

Answer 9

1. improves survival in some patients with systolic HF

2. Will also enhance diuresis and ameliorate the potassium wasting of loop-thiazides at CT

Question 10

loop diuretics: adverse reactions

Answer 10

1. Hypokalemic metabolic alkalosis
2. Predisposes to ectopic pacemakers and arrhythmias
3. Hyperuricemia - may precipitate a gout attack
4. Hypomagnesemia / hypocalcemia
5. Ototoxicity (ethacrynic acid) - higher incidence with diminished renal function and concomitant AGs

Question 11

loop diuretic hypokalemic metabolic alkalosis is caused via

Answer 11

enhanced K+ and H+ excretion - more pronounced than with thiazides

Question 12

thiazide diuretics inhibit

Answer 12

1. Inhibit the Na+/Cl- cotransporter –> increased urinary excretion of NaCl
2. Modest diuretic effect since only 5-10% of filtered Na+ is reabsorbed here
3. Thiazides increase reabsorption of Ca++

Question 13

loop diuretics ____ serum Ca++ levels

Answer 13

decrease

Question 14

thiazide diuretics are secreted by

Answer 14

organic acid secretory system

• competition with uric acid secretion may precipitate a gout attack

Question 15

thiazide used as congestive HF?

Answer 15

1. Higher doses needed than in hypertension and more efficacious diuretics are usually required (loop diuretics)
2. True synergistic diuretic effect with loop diuretics (esp. metolazone) may be useful in refractory edema

Question 16

Potassium- Sparing Diuretics are

Answer 16

Na+-channel Blockers and Aldosterone Antagonists