Chap 15 - Diuretics

Question 1

In which part of the nephron do carbonic anhydrase inhibitors work?

Answer 1

Proximal convoluted tube

Question 2

Where in the nephron do loop diuretics work? Be specific.

Answer 2

Thick ascending loop of Henle

Question 3

Where in the nephron do thiazides work?

Answer 3

Distal convoluted tubule. (Early segment)

Question 4

Where in the nephron do potassium sparing diuretics work?

Answer 4

Cortical collecting ducts.

Question 5

Most diuretics work in the luminal side of the membrane with the exception of which?

Answer 5

Aldosterone receptor antagonist - these enter the collecting tubule cell from the basolateral side.

Question 6

Which part of nephron is responsible for 60-70% of total sodium reabsorption?

Answer 6

Proximal convoluted tube

Question 7

A hypokalemic state has what effect on pH? And a hyperchloremic state?

Answer 7

Increases and decreases respectively.

Question 8

What is the difference between primary and nephrogenic diabetes insipidous?

Answer 8

N: can’t concentrate urine b/c kidneys not responding to ADH. P: can’t concentrate urine b/c not making ADH.

Question 9

What is the class of diuretics that increase uric acid excretion, usually by inhibiting uric acid reabsorption? Example is ethacrynic acid.

Answer 9

Uricosuric diuretic.

Question 10

What is the prototypic agent for the carbonic anhydrase inhibitors class of diuretics?

Answer 10

Acetazolamide

Question 11

Which of the loop diuretics will make you acidotic? Alkalotic?( 2 each )

Answer 11

Carbonic anhydrase inhibitors and k+sparing drugs; loops and thiazides

Question 12

Which of the diuretics gets rid of the most NaCl in urine? Of the most NaHCO3?

Answer 12

Loops and carbonic anhydrase inhibitors respectively.

Question 13

Which of the diuretics has the dual effect of reducing intraocular pressure?

Answer 13

Carbonic anhydrase inhibitors hence they are used to treat severe acute glaucoma.

Question 14

Which diuretic does the following: creates acidosis in CSF which results in hyperventilation which protects against high altitude sickness.

Answer 14

Carbonic anhydrase inhibitors.

Question 15

Under what conditions will acetazolamide be used as a diuretic?

Answer 15

If edema and metabolic alkalosis is present.

Question 16

Drowsiness, paresthesia, and formation of renal stones are common signs of toxicity for which class of diuretics?

Answer 16

CAi

Question 17

At its most severe toxicity, this can lead to hepatic encephalopathy.

Answer 17

CAi, esp in pts with hepatic disease.

Question 18

Which carrier is the target of loop diuretics?

Answer 18

Na+K+2Cl- carrier.

Question 19

Approx what percent of sodium reabsorption is done in the TAL?

Answer 19

20 to 30

Question 20

What is the prototypical loop agent?

Answer 20

Furosemide

Question 21

Ethacrynic acid acts most like which of the diuretics?

Answer 21

Loops.

Question 22

Diuresis of CAi is self-limiting and usually lasts how long? And what about the loops?

Answer 22

2 to 3 days. Short acting 4 hours done.

Question 23

This class of diuretics is mainly used in tx of edematous states such as ascities and heart failure.

Answer 23

Loops

Question 24

Why are loops no good for tx of HTN?

Answer 24

Too short acting

Question 25

Otototoxicity is an important toxic effect of which agent?

Answer 25

Loops

Question 26

The Na+Cl- transporter is the target for which agents?

Answer 26

Thiazides.

Question 27

What is the prototype for thiazide diuretics?

Answer 27

Hydrochlorothiazide.

Question 28

Is the duration of action of thiazides longer or shorter than loops?

Answer 28

Longer at 6-12 hours

Question 29

What happens to urine calcium content with loop diuretics? With thiazides?

Answer 29

Increased. Decreased.

Question 30

Thiazides plus what other diuretic will produce a synergistic effect with marked diuresis?

Answer 30

Loop

Question 31

What is he major clinical application of use for thiazides?

Answer 31

HTN

Question 32

The final segment of the nephron is the last site of Na+ reabsorption and is controlled by what?

Answer 32

Steroid hormone aldosterone.

Question 33

The part of the nephron where reabsorption occurs via channels (ENaC) NOT a transporter.

Answer 33

Cortical collecting ducts

Question 34

What is the primary site of acidification of the urine?

Answer 34

Cortical collecting duct.

Question 35

To what class of drug does amiloride and triamterene belong?

Answer 35

Potassium sparing drugs

Question 36

Aldosteronism is an important indication for which of the diuretics?

Answer 36

Spironolactone

Question 37

Which diuretics should never be given with K+ supplements?

Answer 37

Potassium sparring diuretics.

Question 38

Which of the diuretics can cause gynecomastia and anti-adrenergic effects?

Answer 38

K+ sparring (spironolactone)

Question 39

What is the prototype for osmotic diuretics?

Answer 39

Mannitol

Question 40

How exactly does mannitol work as a drug?

Answer 40

It is poorly reabsorbed (although freely filtered) and as a result it stays in the lumen and keeps water there with it. Remember, these work in the proximal tubule.

Question 41

Which of the diuretics can also reduce brain volume and ITC pressure by osmotically extracting water from tissue in blood?

Answer 41

Mannitol. Note that a similar effect also happens in the eye and is used in treating glaucoma.

Question 42

Which class of diuretics are mainly used to maintain high urine flow?

Answer 42

Osmotic drugs

Question 43

Which class of diuretics are used to treat reduced BF?

Answer 43

Osmotic drugs.

Question 44

Which class of diuretics does desmopressin belong to?

Answer 44

ADH agonists

Question 45

Which class of drugs do conivaptan and tolvaptan belong to?

Answer 45

ADH antagonists

Question 46

Which drug facilitates water reabsorption by activation of v2 recpetors?

Answer 46

ADH. Note that this action increases cAMP which leads to insertion of AQP2 water channels into luminal membrane.

Question 47

Which diuretic drugs are used to treat pituitary diabetes insipidus?

Answer 47

ADH agonists

Question 48

True or false: ADH agonists are useful in the treatment of nephrogenic diabetes insipidus.

Answer 48

False.

Question 49

Which class of diuretics should be used to treat SIADH secretion?

Answer 49

ADH antagonists such as demeclocycline and conivaptan

Question 50

What is the risk of toxicity with ADH?

Answer 50

In presence of large water load may cause hyponatremia.

Question 51

What is the most toxic side effect of lithium?

Answer 51

Nephrogenic diabetes insipidus. FOR THIS REASON, NEVER USE TO TX SIADH. remember, lithium is an ADH antagonist.