Diuretics-1 (1)

Question 1

What do diuretics increase the rate of?

Answer 1

Urine flow (diuresis) and sodium excretion (natriuresis)

Diuretics also affect an accompanying anion, usually Cl-

Question 2

What is the major determinant of extracellular fluid volume affected by diuretics?

Answer 2

NaCl content

Question 3

In which pathophysiological conditions are diuretics generally used?

Answer 3

• Hypertension
• Heart failure
• Renal failure
• Nephrotic syndrome
• Cirrhosis

Question 4

What are the inhibitors of carbonic anhydrase used in diuretics?

Answer 4

• Acetazolamide
• Dichlorphenamide
• Methazolamide

Question 5

What is the major site of action for osmotic diuretics?

Answer 5

Loop of Henle

Question 6

List examples of osmotic diuretics.

Answer 6

• Glycerin
• Isosorbide
• Mannitol
• Urea

Question 7

What do loop diuretics inhibit?

Answer 7

Na+-K+-2Cl– symporter

Examples include Furosemide, Bumetanide, Ethacrynic acid, Torsemide

Question 8

What is the prototype thiazide diuretic?

Answer 8

Hydrochlorothiazide

Question 9

What are examples of thiazide and thiazide-like diuretics?

Answer 9

• Bendroflumethiazide
• Chlorothiazide
• Hydroflumethiazide
• Polythiazide
• Methyclothiazide

Question 10

What do inhibitors of renal epithelial Na+ channels include?

Answer 10

• Triamterene
• Amiloride

Question 11

What are examples of aldosterone antagonists?

Answer 11

• Spironolactone
• Eplerenone

Question 12

What is the function of carbonic anhydrase in the proximal tubular epithelial cells?

Answer 12

Facilitates NaHCO3 reabsorption and acid secretion

Question 13

What is the effect of carbonic anhydrase inhibitors on urinary excretion?

Answer 13

Increases urinary HCO3- excretion to about 35% of filtered load

Question 14

True or False: Carbonic anhydrase inhibitors are effective as monotherapy against edema.

Answer 14

False

Question 15

What is a major drawback of long-term use of carbonic anhydrase inhibitors?

Answer 15

Metabolic acidosis

Question 16

How do osmotic diuretics affect blood viscosity?

Answer 16

Reduce blood viscosity

Question 17

What therapeutic uses do osmotic diuretics have?

Answer 17

• Increase urine volume in acute tubular necrosis
• Prophylactic use in jaundiced patients during surgery
• Treatment of dialysis disequilibrium syndrome
• Control intraocular pressure during acute attacks of glaucoma

Question 18

What is the mechanism of action of carbonic anhydrase in the renal proximal tubule?

Answer 18

Accelerates breakdown of H2CO3 to form water and CO2

Question 19

What happens to bicarbonate ions in the renal collecting duct due to carbonic anhydrase inhibitors?

Answer 19

Inhibition of titratable acid and NH4+ secretion

Question 20

What is the effect of carbonic anhydrase inhibitors on renal blood flow and glomerular filtration rate?

Answer 20

Reduces renal blood flow and glomerular filtration rate

Question 21

What is the impact of osmotic diuretics on renal medullary blood flow?

Answer 21

Increases renal medullary blood flow

Question 22

What is the primary use of osmotic diuretics?

Answer 22

Control intraocular pressure (IOP) during acute attacks of glaucoma and for short-term reductions in IOP in patients requiring ocular surgery.

Question 23

Name some examples of Loop Diuretics or High-ceiling Diuretics.

Answer 23

• Furosemide
• Bumetanide
• Ethacrynic acid
• Torsemide

Question 24

What do Loop Diuretics inhibit in the nephron?

Answer 24

Na+-K+-2Cl– symporter in the thick ascending limb.

Question 25

What is the effect of the Na+-K+-2Cl– symporter on cation transport?

Answer 25

It creates a transepithelial potential difference that repels cations (Na+, Ca2+, and Mg2+) into the interstitium.

Question 26

How do Loop Diuretics affect urinary excretion of Na+ and Cl-?

Answer 26

They greatly increase the urinary excretion of Na+ and Cl- (up to 25% of the filtered load of Na+).

Question 27

What happens to the excretion of Ca2+ and Mg2+ when Loop Diuretics are used?

Answer 27

Excretion of Ca2+ and Mg2+ is profoundly enhanced.

Question 28

How do Loop Diuretics influence renal blood flow?

Answer 28

They enhance renal blood flow.

Question 29

What therapeutic uses are associated with Loop Diuretics?

Answer 29

* Hypertension * Edema and ascites of hepatic cirrhosis * Chronic congestive heart failure * Hypercalcemia * Inducing forced diuresis in drug overdose

Question 30

What is Diuretic Resistance?

Answer 30

The inability to increase fluid and sodium output sufficiently to relieve volume overload, edema, or congestion despite high doses of a loop diuretic.

Question 31

List some causes of Diuretic Resistance.

Answer 31

* Poor compliance to drug therapy * High daily salt intake * Hyponatremia or hypokalemic * Hypochloremic metabolic alkalosis * Pharmacokinetic issues * Compensatory Na+ reabsorption

Question 32

True or False: Diuretic Resistance can be related to diuretic braking.

Answer 32

True

Question 33

What is diuretic braking?

Answer 33

A gradual reduction of a patient's response to a diuretic after the first dose, leading to decreased effectiveness over time.

Question 34

What mechanisms are involved in diuretic braking?

Answer 34

* Activation of the sympathetic nervous system * Activation of the renin-angiotensin-aldosterone axis * Reduction of arterial blood pressure * Hypertrophy of renal epithelial cells * Increased expression of renal epithelial transporters * Alterations of atrial natriuretic peptide