Pharmacology - Exam 4 - 2.2 Diuretics

Front 1

Drugs used in renal disorders are grouped into two categories, what are they?

Back 1

1. Drugs that modify salt excretion
2. Drugs that modify water excretion

Front 2

Drugs that modify salt excretion work on different parts of the nephron. Group the class of drug with the appropriate part of the nephron.

Back 2

1. PCT - Carbonic anhydrase inhibitors
2. TAL - Loop diuretics
3. DCT - Thiazides
4. CCT - K+-sparing diuretics
5. Osmotic diuretics

Front 3

Drugs that modify water excretion can be classified into three groups of drugs. What are they?

Back 3

1. Osmotic diuretics
2. ADH agonists
3. ADH antagonists

Front 4

Prototypes and mechanism of action of carbonic anhydrase inhibitors?

Back 4

1. Acetazolamide, a sulfonamide derivative.
2. Inhibits carbonic anhydrase in the brush border and intracellular carbonic anhydrase in the PCT cells

Front 5

Major effect of carbonic anhydrase inhibitors?

Back 5

1. Bicarbonate diuresis; body bicarbonate is thus depleted, and metabolic acidosis results.
2. In the CNS, acidosis of the CSF results in hyperventilation, which can protect against high-altitude sickness

Front 6

Clinical uses of carbonic anhydrase inhibitors?

Back 6

1. Treatment of glaucoma
2. Prevent acte mountain sickness
3. Only used for their diuretic effect if edema is accompanied by significant metabolic alkalosis

Front 7

Prototypes and mechanism of action of loop diuretics?

Back 7

1. Furosemide
2. Bumetanide
3. Ethacrynic acid
4. The first two are sulfonamide derivatives, ethacrynic acid is a phenoxyacetic acid derivative.
5. Inhibit the co-transport of sodium, potassium, and chloride.

Front 8

Effects of loop diuretics?

Back 8

1. Massive sodium chloride diuresis
2. Edema fluid is rapidly excreted and blood volume may be significantly reduced
3. Calcium excretion is significantly increased
4. Ethacrynic acid is a moderate uricosuric agent
5. Hypokalemic alkalosis may occur

Front 9

Clinical use of loop diuretics?

Back 9

1. Major use in edematous states (heart failure, ascites, pulmonary edema)
2. Sometimes used in HTN if thiazides are inadequate
3. Treatment of hypercalcemia

Front 10

Important toxicities of loop diuretics?

Back 10

1. Hypokalemic metabolic acidosis
2. Hypovolemia and CVS complications
3. Ototoxicity

Front 11

Prototypes and mechanism of action of thiazides?

Back 11

1. Hydrochlorothiazide, and all the other members of this group are suflonamide derivatives.
2. Active by the oral route
3. Inhibits sodium chloride transport in the early segment of the DCT

Front 12

Four thiazide diuretics?

Back 12

1. Hydrochlorothiazide
2. Chlorothiazide
3. Chlorthalidone
4. Indapamide

Front 13

The major effects of thiaizide diuretics?

Back 13

1. Sodium and chloride diuresis
2. Hypokalemic metabolic alkalosis may occur
3. Reabsorption of calcium from the urine is increased, and the urine calcium content is decreased - the opposite of loop diuretics
4. Reduction of blood pressure

Front 14

Clinical uses of thiazides?

Back 14

1. Reduction of blood pressure
2. Chronic therapy of edematous conditions
3. Chronic renal calcium stone formation

Front 15

Toxicities of thiazides?

Back 15

1. Massive sodium diuresis with hyponatremia
2. Potassium wasting
3. Significant hypoglycemia in diabetic patients
4. Serum lipid and uric acid levels are also increased in some patients

Front 16

Prototypes and mechanism of action of potassium sparing diuretics?

Back 16

1. Spironolactone
2. Amilioride
3. Triamterene

4. Steroid derivatives and act as pharmacologic antagonists of aldosterone in the collecting tubule.
5. Reduce the expression of genes controlling synthesis of epithelial sodium ion channels and Na/K-ATPase

Front 17

Effects of potassium sparing diuretics?

Back 17

1. Increase sodium clearance and decrease in potassium and hydrogen exchange.
2. May cause hyperkalemic metabolic acidosis

Front 18

clinical use of potassium sparing diuretics?

Back 18

1. Aldosteronism is an important indication for spironolactone
2. Potassium wasting caused by chronic use of loop or thiazide diuretics

Front 19

Toxicities of potassium sparing diuretics?

Back 19

1. Hyperkalemia
2. Spironolactone may cause endocrine abnormalities, including gynecomastia and antiandrogenic effects

Front 20

Prototype and mechanism of action of osmotic diuretics?

Back 20

1. Mannitol
2. Freely filtered at the glomerulus but poorly reabsorbed from the tubule. They hold water by an "osmotic" effect. The major location of action is the PCT

Front 21

Effects of osmotic diuretics?

Back 21

1. Increase urine output
2. Reduce brain volume and ICP. A similar effect occurs in the eye

Front 22

Clinical use of osmotic diuretics?

Back 22

1. Maintain high urine flow
2. Reduce IOP in acute glaucoma and neurologic conditions

Front 23

Toxicities of osmotic diuretics?

Back 23

1. Hyponatremia
2. Pulmonary edema
3. Headache, nausea, and vomiting are common

Front 24

Prototypes and mechanism of action of ADH agonists and antagonists

Back 24

1. ADH and desmopressin - agonists
2. Demeclocycline and lithium ion are ADH antagonists

3. ADH activates V2 receptors, facilitating water reabsorption from the CCT. Antagonists block these.

Front 25

Effects and clinical uses of ADH agonists/antagonists

Back 25

1. ADH and desmopressin reduce urine volume and increase its concentration. Useful in pituitary diabetes insipidus.
2. SIADH can be treated with demeclocycline; lithium also works but with a greater toxicity

Front 26

Toxicities of ADH antagonists/agonists

Back 26

1. ADH or desmopressin may cause dangerous hyponatremia
2. In children younger than 8 years, demeclocycline (and other tetracyclines) causes bone and teeth abnormalities
3. Lithium causes nephrogenic diabetes insipidus; because of its other toxicities lithium is never used to treat SIADH.

Front 27

What is a bicarbonate diuretic?

Back 27

A diuretic that selectively increases bicarbonate excretion. Example: a carbonic anhydrase inhibitor

Front 28

What is the diluting segment?

Back 28

A segment of the nephron that removes solute without water; TAL and DCT are active salt-absorbing segments that are not permeant to water

Front 29

What is hyperchloremic metabolic acidosis?

Back 29

A shift in body electrolyte and pH balance involving elevated chloride, diminished bicarbonate concentration, and a decrease in pH in the blood. Typical result of bicarbonate diuresis

Front 30

What is a bicarbonate diuretic?

Back 30

A diuretic that selectively increases bicarbonate excretion. Example: a carbonic anhydrase inhibitor

Front 31

What is hypokalemic metabolic alkalosis?

Back 31

A shift in body electrolyte balance and pH involving a decrease in serum potassium and an increase in blood pH. Typical result of loop and thiazide diuretic actions

Front 32

What is the diluting segment?

Back 32

A segment of the nephron that removes solute without water; TAL and DCT are active salt-absorbing segments that are not permeant to water

Front 33

What is hyperchloremic metabolic acidosis?

Back 33

A shift in body electrolyte and pH balance involving elevated chloride, diminished bicarbonate concentration, and a decrease in pH in the blood. Typical result of bicarbonate diuresis

Front 34

What is nephrogenic diabetes insipidus?

Back 34

Loss of urine-concentrating ability in the kidney caused by lack of responsiveness to ADH (ADH is normal or high)

Front 35

What is pituitary diabetes insipidus?

Back 35

Loss of urine-concentrating ability in the kidney caused by lack of ADH (ADH is low or absent)

Front 36

What is hypokalemic metabolic alkalosis?

Back 36

A shift in body electrolyte balance and pH involving a decrease in serum potassium and an increase in blood pH. Typical result of loop and thiazide diuretic actions

Front 37

What is nephrogenic diabetes insipidus?

Back 37

Loss of urine-concentrating ability in the kidney caused by lack of responsiveness to ADH (ADH is normal or high)

Front 38

What are potassium-sparing diuretics?

Back 38

A diuretic that reduces the exchange of potassium for sodium in the CCT; a drug that increases sodium and reduces potassium excretion. Example: aldosterone antagonists

Front 39

What is pituitary diabetes insipidus?

Back 39

Loss of urine-concentrating ability in the kidney caused by lack of ADH (ADH is low or absent)

Front 40

Uricosuric diuretic?

Back 40

A diuretic that increases uric acid excretion, usually by inhibiting uric acid reabsorption in the PCT. Example: ethacrynic acid

Front 41

What are potassium-sparing diuretics?

Back 41

A diuretic that reduces the exchange of potassium for sodium in the CCT; a drug that increases sodium and reduces potassium excretion. Example: aldosterone antagonists

Front 42

Uricosuric diuretic?

Back 42

A diuretic that increases uric acid excretion, usually by inhibiting uric acid reabsorption in the PCT. Example: ethacrynic acid