Exam 1; Diuretics

Question 1

What is the definition of a diuretic

Answer 1

any agent that causes a net excretion of water and Na+

Question 2

What two main things are diuretics used for clinically

Answer 2

hypertension; decreasing blood volume and some cause vasodilation
to reduce edema; in heart failure; kidney retains H2O and Na, water accumulates in the interstitial space

Question 3

This is designed to eliminate unwanted molecules (Na & H2O) and to conserve essential ions and molecules

Answer 3

normal kidney function

Question 4

What is the flow of molecules in the proximal convoluted tubule

Answer 4

removal of Ca++, Na+, HCO3-

exchange of organic molecules

Question 5

What is the flow of water through the renal tubule

Answer 5

water can freely pass through the tubule; following the osmotic gradient

Question 6

What is the flow of molecules in the loop of Henle

Answer 6

removal of K+, Cl-, and large amounts of Na

Question 7

What is the flow of molecules in the distal convoluted tubule

Answer 7

removal of Na+, Cl-, Ca++

Question 8

What is the flow of ions in the collecting duct

Answer 8

Na+/K+ exchanger (Na out, K in)

removal of H2O

Question 9

True or False

Thiazide diuretics have a low therapeutic index

Answer 9

False; they have a high index

Question 10

What is the mechanism behind thiazide diuretics

Answer 10

they inhibit Na+ transport out of the DCT; water follows and they are excreted in the urine

Question 11

What are two other affects of thiazide diuretics

Answer 11

they cause direct vasodilation (often drug of choice in treating hypertension)
they decrease the excretion of Ca++ (Ca++ retention)

Question 12

What are five side effects of thiazide diuretics

Answer 12

hypokalemia (loss of Ka due to Na/K exchanger)
increase serum LDL and triglycerides
decrease uric acid secretion; gout
inhibit insulin secretion
contains sulfur ions; may cause allergic reaction

Question 13

What are two examples of thiazide diuretics

Answer 13

chlorothiazide

hydrochlorothiazide

Question 14

What are four examples of loop/high ceiling diuretics

Answer 14

furosemide
ethacryncic acid
bumetanide
torsemide

Question 15

What is the mechanism of action of loop diuretics

Answer 15

given orally or parentally

inhibit Na/Cl resorption from the ascending limb of the loop of Henle

Question 16

Which is more efficacious, thiazides or loop diuretics

Answer 16

loop

Question 17

How much urine/day can a patient excrete while on loop diuretics

Answer 17

10L

Question 18

When are loop diuretics given clinically

Answer 18

in patients that don’t respond well to thiazides
patients with impaired renal function
patients with life threatening edema (pulmonary/cerebral)

Question 19

What are 5 side effects of loop diuretics

Answer 19

dehydration
hypokalemia (more Na to exchanger)
hypocalcemia (increase Ca excretion)
decreased uric acid secretion
auditory nerve damage (especially if used with other ototoxic agents)

Question 20

What are two examples of potassium-sparing diuretics; aldosterone antagonists

Answer 20

spironolactone

eplerenone

Question 21

What is the mechanism behind potassium-sparing diuretics

Answer 21

blocking the aldesterone receptor; can prevent synthesis of Na/K+ exchanger

Question 22

What are four side effects of potassium-sparing diuretics

Answer 22

takes a couple days to work
used with other diuretics to prevent K+ loss
used to treat excess aldesterone activity
can cause hyperkalemia

Question 23

This potassium-sparing diuretic is a steroid, and can have anti-androgen effects (breast growth, etc.)

Answer 23

spironolactone

Question 24

This potassium sparing diuretic has fewer interaction with other steroid receptors

Answer 24

eplerenone

Question 25

These two potassium-sparing diuretics are inhibitors of what

Answer 25

triamterne
amiloride
Na+ transport in the distal tubule and collecting duct

Question 26

Potassium-sparing diuretics which inhibit Na transport have what kind of mechanism

Answer 26

they prevent Na from getting into the exchanger by blocking Na channel

Question 27

What is the effect/symptoms of potassium sparing diuretics which inhibit Na transport

Answer 27

the effect is more rapid and predictable than alderstone antagonists
hyperkalemia

Question 28

What is the mechanism behind carbonic anhydrase (enzyme) inhibitors

Answer 28

inhibits HCO3- absorption in the PCT

Question 29

What three things do carbonic anhydrase inhibitors (not primarily a diuretic) also treat

Answer 29

open angle glaucoma
mountain sickness (decrease CSF formation)
epilepsy (may be due to pH changes in the CNS)

Question 30

This is an example of an osmotic diuretic

Answer 30

mannitol

Question 31

What is the mechanism behind mannitol

Answer 31

non-metabolized sugar given as an IV and it remains in tubule and draws water into tubule and is secreted with the water

Question 32

What is mannitol used to treat

Answer 32

used to maintain renal/urine flow after renal damage/trauma

also it lowers intracranial pressure

Question 33

This diuretic increases globular filtration rate

Answer 33

methylxanthines (such as caffeine)

Question 34

This diuretic releases ADH

Answer 34

ethanol

Question 35

This triggers the synthesis of the Na/K exchanger

Answer 35

aldesterone

Question 36

ADH (antidiuretic hormone) induces what

Answer 36

further reabsorption of H2O

Question 37

This blocs the ADH receptor; in cases of excess ADH/retain too much water

Answer 37

conivaptin