Easy pharmacology

Question 1

Which carrier do loop diuretics inhibit and which ion bit do they bind to?

Answer 1

Na+/K+/2Cl-

Bind to chlorine

Question 2

Which other ions are excreted when you use loop diuretics?

Answer 2

Ca 2+ and Mg 2+

Question 3

Additional effects of loop diuretics?

Answer 3

Venodilator

-beneficial in pulmonary oedema caused by heart failure

Question 4

Which transporter do thiazide diuretics block?

Answer 4

The Na+/Cl-

bind to the Cl- site

Question 5

Thiazide diuretics, calcium and magnesium

Answer 5

Inhibit secretion of calcium (i.e. less will be excreted)

Increase excretion of magnesium

Question 6

Additional effects of thiazide diuretics

Answer 6

Vasodilator (can be used in hypertension)

Question 7

Type of diuretic used in renal stone disease?

Answer 7

Thiazide

reduced excretion of calcium discourages stone formation

Question 8

Type of diuretic used in nephrogenic diabetes?

Answer 8

Thiazide diuretic, mechanism poorly understood

Question 9

Diuretics associated with male sexual dysfunction?

Answer 9

Thiazide diuretics

Question 10

Diuretics associated with impaired glucose tolerance?

Answer 10

Thiazide diuretics

Question 11

Aldosterone and the Na+/K+ATPase?

Answer 11

Aldosterone increases synthesis of the Na+/K+ATPase

Question 12

What is ENaC?

Answer 12

Epithelial Na+ channel

Question 13

Which hormone increases production of ENaC?

Answer 13

Aldosterone

Question 14

ADH and aquaporins (H20 channels) in the cell membrane?

Answer 14

ADH increases the number of these channels

Question 15

Why do loop and thiazide diuretics cause potassium loss?

Answer 15

There is an increased Na+ load in the tubule because loop/thiazide diuretic prevented its reabsorption earlier

–> increased Na+ reabsorption –>

Membrane becomes depolarised –>

K+ and H+ are secreted

Question 16

Which channel do Amiloride and Triamterene block?

Answer 16

Block the apical Na channel and decrease Na reabsorption

Question 17

How do spironolactone and eplerenone work?

Answer 17

Compete with aldosterone for binding to intracellular receptors (cytoplasmic receptors)

• cause decreased synthesis of protein which activates Na+ channel
• decreased numbers of Na+/K+ ATPase pumps in the basolateral membrane

Question 18

Canrenone?

Answer 18

Spironolactone is metabolised to canrenone which accounts for most of the action of the drug

Question 19

How are spironolactone and eplerenone absorbed?

Answer 19

Absorbed from the GI tract

Question 20

Triamterene and Amiloride and GI absorption?

Answer 20

Triamterene is absorbed well

Absorption of amiloride is poor

Question 21

…used in the treatment of:

Heart failure
Primary hyperaldosteronism (Conn’s syndrome)
Resistant essential hypertension
Secondary hyperaldosteronism (due to hepatic cirrhosis with ascites)

Answer 21

Aldosterone antagonists

Question 22

Why can loop/thiazide diuretics cause alkalosis?

Answer 22

Cause excretion of H+

Question 23

How does aldosterone work?

Answer 23

1) Increases synthesis of Na+/K+ ATPase

2) Increases synthesis of a protein that activates the epithelial Na+ channel (ENAc)

Question 24

Why do you give mannitol IV?

Answer 24

because it is membrane impermeable

Question 25

Where does mannitol work?

Answer 25

Proximal tubule

Question 26

How do carbonic anhydrase inhibitors work? (tricky)

Answer 26

Increase excretion of HCO3 with Na+, K+ and H2O (alkaline diuresis and metabolic acidosis will result)

Question 27

How do carbonic anhydrase inhibitors work? (tricky)

Answer 27

Increase excretion of HCO3 with Na+, K+ and H2O (alkaline diuresis and metabolic acidosis will result)

Question 28

What do V1 receptors mediate?

Answer 28

Mediate vasoconstriction

Question 29

What do V2 receptors mediate?

Answer 29

H2O absorption

Question 30

How do vaptans work?

Answer 30

Blockade of V2 receptors
-cause excretion of water without accompanying Na+
(thus raise plasma Na+ )

Question 31

Drug used to treat SIADH

Answer 31

Tolvaptan

Question 32

How is glucose reabsorbed at the apical/basolateral membrane

Answer 32

Secondary active transport (apical)

Facilitated diffusion (basolateral)

Question 33

How do SGLT2 inhibitors work?

Answer 33

Excretion of glucose
Decrease in HbA1c
Weight loss

Question 34

Where is PGE2 made?

Answer 34

The medulla

Question 35

Where is PGI2 made?

Answer 35

Glomeruli

Question 36

How do prostaglandins affect GFR?

Answer 36

• vasodilator effect on afferent arteriole

- release renin = vasoconstricts efferent arteriole

Question 37

This acid is made by the catabolism of purines

Answer 37

Uric acid

Question 38

How do uricosuric agents work?

probenicid, sulfinpyrazole

Answer 38

Block reabsorption of urate (don’t cause enhanced excretion, just block reabsorption)