test 6 part 2

Question 1

Diuretics

Answer 1

 Increase the volume of urine excreted

Question 2

Proximal convoluted tubule reabsorption

Answer 2

 Almost 100%: glucose, amino acids, metabolites

 65%: H2O, Na, Cl, K, bicarbonate

Question 3

Proximal convoluted tubule secretion

Answer 3

 H+
 Organic acids and bases
 Catecholamines
 Drugs/toxins

Question 4

Descending loop of henle

Answer 4

• H2O reabsorbed

Question 5

Ascending loop of henle reabsorbed

Answer 5

 Impermeable to water!
 25%: Na, Cl, K
 Ca, bicarbonate, magnesium

Question 6

Ascending loop of henle secreted

Answer 6

 H+

Question 7

Early Distal convoluted tubule

Answer 7

 Impermeable to water!

 5%: Na, Cl, K reabsorbed

Question 8

Late distal tubule and cortical collecting tubule reabsorbed

Answer 8

 H2O in the presence of Antidiuretic hormone (ADH)
 Principal cells
        - Na+
 Intercalated cells
        - Bicarb, K+, and H+

Question 9

Late distal tubule and cortical collecting tubule excreted

Answer 9

 Principal cells
- K+
 Intercalated cells
- Bicarb, K+, and H+

Question 10

Medullary collecting duct reabsorbed

Answer 10

 10%: Na, H2O (when ADH present)

 Urea

Question 11

Medullary collecting duct secreted

Answer 11

 H+

Question 12

Common uses of diuretics

Answer 12

Hypertension
Edema associated with
         Congestive heart failure
         Liver cirrhosis
         Corticosteroid therapy
         Renal dysfunction

Question 13

Types of diuretics

Answer 13

Thiazide
Loop
Potassium-Sparing
Carbonic Anhydrase Inhibitors
Osmotic

Question 14

Thiazide diuretics

Answer 14

Most widely used
Affect distal convoluted tubule
All have same Emax, different potencies
Effective orally
1-3 weeks for stable blood pressure reduction
- “low ceiling diuretics” = giving more than therapeutically required won’t do anything

Question 15

Thiazide diuretics affect which transporter

Answer 15

• Na/Cl cotransporter on luminal membrane

- in distal convoluted tubule

Question 16

Thiazide diuretics enter lumen where and how

Answer 16

• Secreted into the lumen in the proximal tubule via the organic acid secretory system

Question 17

Thiazide diuretic actions

Answer 17

 Increased excretion of Na and Cl
 Very hyperosmolar urine
 Unique to thiazides
 Loss of K+ (Na/K countertransport mech on luminal side)
 Sodium concentration in filtrate is high when it reaches distal tubule
 More K+ is exchanged for Na+
 Loss of Mg2+ (supplementation of Mg2+ required with chronic use)
 Decreased excretion of calcium
 Increased reabsorption in distal convoluted tubule
 Reduced PVR
 Over time volume status returns but PVR remains low

Question 18

Thiazide diuretics therapeutic uses

Answer 18

 Hypertension
 Heart failure
 Hypercalciuria
 Diabetes insipidus

Question 19

Thiazide diuretics adverse effects

Answer 19

 Potassium depletion
 Hyponatremia
 Hyperuricemia
 Volume depletion
 Hypercalcemia
 Hyperglycemia

Question 20

Loop diuretics

Answer 20

 Major action on ascending Loop of Henle
 Act on luminal side
 Highest efficacy in removing Na+ and Clfrom
the body
 Produce copious amounts of urine
 Oral or IV
 Rapid onset, short duration (2-4 hours)
- greatest diuretic effect

Question 21

Loop diuretics act on what transporter

Answer 21

• Na/2Cl/K cotransporter luminal membrane

- ascending loop of henle

Question 22

Loop diuretics and renal blood flow

Answer 22

 Quick response
 May increase renal blood flow due to prostaglandin synthesis
 NSAIDS inhibit renal prostaglandin synthesis and can reduce the diuretic action

Question 23

Loop diuretics therapeutic uses

Answer 23

 Peripheral and pulmonary edema (HF)
 Emergency situations (Acute pulmonary edema)
 Hypercalcemia
 Hyperkalemia
- Diuretic of choice even in patients with compromised renal function

Question 24

Loop diuretics perfusion uses

Answer 24

 Remove extra fluid on CPB
 Treat hyperkalemia
 Help maintain urine production and renal function

Question 25

Adult pump dose of loop diuretics

Answer 25

20-40 mg bolus

Question 26

Loop diuretics adverse effects

Answer 26

```  Ototoxicity  Hyperuricemia  Acute hypovolemia  Potassium depletion  Hypomagnesemia ```

Question 27

Potassium-sparing diuretics: aldosterone antagonists

Answer 27

 Block aldosterone action  Mediator proteins that normally stimulate the Na+/K+ pump are not produced  Retention of K+  Excretion of Na+

Question 28

Potassium-sparing diuretics: aldosterone antagonists therapeutic uses

Answer 28

 Diuresis  Low efficacy in removing Na+ from body  Useful for retention of K+  Given in conjunction with thiazide or loop diuretics  Secondary hyperaldosteronism  Hepatic cirrhosis  Nephrotic syndrome  Heart failure  Resistant hypertension  Ascites  Polycystic ovary syndrome (high androgen levels)

Question 29

Potassium-sparing diuretics: aldosterone antagonists adverse effects

Answer 29

 Gynecomastia in male patients  Menstrual irregularities in female patients  Hyperkalemia  Mental confusion

Question 30

Potassium-sparing diuretics: Sodium channel blockers

Answer 30

- the Na/K counterstransport blocked  Not very efficacious  Used in combination with other diuretics for potassium sparing effects  Prevent the loss of potassium that occurs with thiazide and loop diuretics

Question 31

Potassium-sparing diuretics: Sodium channel blockers adverse effects

Answer 31

 Increased uric acid  Renal stones  K+ retention

Question 32

Carbonic Anhydrase inhibitors

Answer 32

 Much less efficacious than thiazide or loop diuretics  Often used for other pharmacologic actions  Inhibits carbonic anhydrase of proximal tubule

Question 33

Carbonic Anhydrase inhibitors therapeutic uses

Answer 33

 Glaucoma  Correction of metabolic alkalosis  Mountain sickness

Question 34

Osmotic diuretics - Mannitol (osmitrol)

Answer 34

 Alcohol and a sugar (similar to xylitol or sorbitol)  Not absorbed orally  IV

Question 35

Osmotic diuretics - Mannitol (osmitrol) mechanism of action

Answer 35

 Elevates blood plasma osmolality  Enhanced flow of water from tissues into the plasma  Elevates tubular filtrate osmolality  Filtered, but not reabsorbed  Facilitates water excretion  Reduces water reabsorption  Inhibits reabsorption of sodium, chloride, and other solutes

Question 36

Osmotic diuretics therapeutic uses

Answer 36

```  Reduce intracranial pressure  Acute renal failure  Shock  Drug toxicity  Trauma  Maintaining urine flow preserves long term kidney function! ```