Diuretics and Anti-diuretics

Question 1

What are Furosemide and Bumetanide?

Answer 1

Loop diuretics

Question 2

What are examples of thiazide diuretics?

Answer 2

Chlorthalidone
Hydrochlorothiazide
Metalazone

Question 3

Which diuretics are potassium sparing?

Answer 3

Spironolactone

Amiloride and Triamterene

Question 4

What are Vasopressin, desmopressin, and demecocycline?

Answer 4

ADH agents

Demecocycline is an antagonist

Question 5

What is an example of an osmotic diuretic?

Answer 5

Mannitol

Question 6

What is acetazolamide?

Answer 6

Carbonic Anhydrase inhibitor

Question 7

What is the mechanism of action of loop diuretics?

Answer 7

Inhibit Na+/K+/2Cl- pump in thick ascending limb –> increased excretion of Na+, Cl-, K+, and water

Question 8

What is the mechanism of action of Chlorthalidone, hydrochlorothiazide, and metalazone? What is the effect?

Answer 8

Block the Na+/Cl- transporter in the distal convoluted tubule
–> increased excretion of Na+, Cl-, K+, and water

Also, binds to SUR–>open K+ channel–> hyperpolarization of smooth muscle cells–> vasodilation

Reduces HR and TPR–> decreased BP

Question 9

How is potassium lost if it is an Na+/Cl- symporter that is blocked?

Answer 9

K+ is exchanged for the increased Na+ in the cortical collecting tubule

Question 10

What is the mechanism of action of spironolactone?

Answer 10

Inhibition of aldosterone receptors

Question 11

What does aldosterone usually do? Why is it beneficial to antagonize it?

Answer 11

Aldosterone activates the tsx/synthesis of Enac, activates Na+/K+ exchangers, that normally cause retention of Na+ and excretion of K+

Inhibition–>increased excretion of Na+ and water, and increased retention of K+

Question 12

What is the mechanism of action of amiloride and triamterene? What is the effect?

Answer 12

Inhibition of Na+/K+,H+ exchangers and Enac (Na+ channel)

–> increased excretion of Na+ and water, increased retention of K+

Question 13

What is the effect of ADH agonists?

Answer 13

Bind to V2 receptors–> stimulate GPCR–>cAMP

–>aquaporin recruitment–>increased water retention

Question 14

What is the mechanism/effect of mannitol?

Answer 14

Mannitol increases osmolarity–>increased water excretion

Question 15

What is the mechanism/effect of carbonic anhydrase inhibitors?

Answer 15

Inhibit HCO3- reabsorption–>increased water excretion

Question 16

Is acetazolamide generally used long term?

Answer 16

No…leads to increased NaCl reabsorption after a few days, also many side effects

Question 17

When are loop diuretics used?

Answer 17

Pulmonary edema
Other edematous conditions
Hyperkalemia
Acute renal failure
Anion overdose

Question 18

What are thiazide diuretics used for?

Answer 18

HTN
CHF
Nephrolithiasis caused by hypercalcemia
Nephrogenic diabetes insipidus

Question 19

What causes nephrogenic diabetes insipidus?

Answer 19

No ADH receptors in kidneys

Question 20

What are the side effects of thiazide diuretics?

Answer 20

Hyperglycemia
Hyperuricemia
Hypokalemia
Hyperlipidemia
Hyponatremia
Allergic reactions

Question 21

What causes thiazide diuretics to produce hyperglycemia?

Answer 21

They bind to SUR (sulfonyl urea receptor) on K+ channel controlling insulin release→opens the channel and hyperpolarizes the β cell→suppression of insulin release

Question 22

What conditions are thiazide diuretics used to treat? (according to JNC VII)

Answer 22

Risk of stroke
CAD
CHF
DM

Question 23

What conditions should thiazide diuretics NOT be used?

Answer 23

Post MI

Chronic kidney disease

Question 24

Why is it beneficial for an ACE inhibitor to be added to a thiazide regimen?

Answer 24

Thiazides increase tubular Na+–>increased renin
–>increased aldosterone–>increased Na+ reabsorption

ACE inhibitors inhibit the renin–>aldosterone

Question 25

Besides preventing potassium wasting, when else are potassium sparing diuretics used?

Answer 25

Hyperaldosteronism Post MI CHF

Question 26

What are the side effects of potassium sparing diuretics?

Answer 26

``` Hyperkalemia Hyperchloremic metabolic acidosis Gynectomastia (spironolactone) Acute renal failure (triamterene) Kidney stones ```

Question 27

When are ADH agonists used? (Vasopressin, Desmopressin)

Answer 27

Diabetes insipidus | Bedwetting

Question 28

When is mannitol used?

Answer 28

To reduce body water | To reduce intracranial/intraocular pressure

Question 29

What toxicities does mannitol have?

Answer 29

``` Extracellular volume expansion Dehydration Hyperkalemia Hypernatremia Hyponatremia when renal function is impaired ```

Question 30

When are carbonic anhydrase inhibitors used?

Answer 30

Glaucoma To produce urinary alkalinization Metabolic alkalosis (treated with volume and Cl-) Acute mountain sickness

Question 31

What are the side effects of carbonic anhydrase inhibitors?

Answer 31

Hyperchloremic metabolic acidosis Renal stones Renal potassium wasting

Question 32

What causes the hyperuricemia associated with loop diuretics and thiazides?

Answer 32

Hypovolemia-associated uric acid reabsorption

Question 33

Where does ADH originate?

Answer 33

Posterior pituitary

Question 34

What stimulates ADH release?

Answer 34

Changes in plasma volume | Cholestcystokinin (from small intestine)