Pharmacology

Question 1

four sites of diuretic action in the nephron

Answer 1

1. PCT
2. thick ascending loop of Henle
3. early DCT
4. collecting duct

Question 2

transporters in the PCT

Answer 2

Na+ (passive Cl- absorption)

Na+/H+ exchange

Question 3

what blocks Na+/H+ exchange in the PCT and early DCT?

Answer 3

carbonic anhydrase inhibitors

Question 4

what transporter is present in the thick ascending loop of Henle?

Answer 4

Na+/K+/2Cl- co-transporter

Question 5

what blocks the Na+/K+/2Cl- co-transporter in the thick ascending loop of Henle?

Answer 5

loop diuretics

Question 6

transporters in the early DCT

Answer 6

Na+/H+ exchange

Na+/Cl- co-transport

Question 7

what blocks Na+/Cl- co-transporter in the early DCT?

Answer 7

thiazides

Question 8

transporter present in collecting ducts

Answer 8

Na+/K+ exchange

Question 9

what blocks Na+/K+ exchange in the collecting duct?

Answer 9

potassium-sparing diuretics

Question 10

two ways diuretics can enter the filtrate?

Answer 10

1. glomerular filtration

2. secretion

Question 11

which drugs can enter the filtrate by glomerular filtration?

Answer 11

drugs not bound to large plasma proteins

Question 12

two transport processes that secrete components into the filtrate

Answer 12

1. organic anion transporters (OATs)

2. organic cation transporters (OCTs)

Question 13

which drugs can enter the filtrate via OATs?

Answer 13

acidic/negatively charged

PAH, thiazides and loop

Question 14

which drugs can enter the filtrate by OCTs?

Answer 14

basic/ positively charged

triamterene and amiloride

Question 15

examples of loop diuretics

Answer 15

furosemide

bumetanide

Question 16

action of loop diuretics

Answer 16

inhibit Na+/K+/2Cl- in PCT by binding to the Cl- site

Question 17

what do loop diuretics cause excretion of?

Answer 17

Na+
K+
Ca2+
Mg2+

Question 18

when are loop diuretics contra-indicated?

Answer 18

severe hypovolvaemia

dehydration

Question 19

adverse of loop diuretics

Answer 19

hypokalaemia (use potassium-sparing diuretics)
metabolic alkalosis (Na+/H+ transporter)
hypocalcaemia
hypomagnesemia
hypovolaemia
hyperuricaemia
dose-related hearing loss

Question 20

example of a thiazide diuretic

Answer 20

bendroflumethiazide

Question 21

action of thiazide diuretics

Answer 21

inhibit Na+/Cl- binding to Cl- site in early DCT

Question 22

what do thiazides cause in the body?

Answer 22

increases Na+ in the collecting duct causing K+ loss and reabsorption of calcium

Question 23

adverse of thiazides

Answer 23

hypokalaemia
metabolic alkalosis
hypovolaemia
hypomagnesemia (not calcium so used in elderly with OP)
hyperuricaemia
ED
impaired glucose tolerance in diabetes

Question 24

what receptors does aldosterone act on?

Answer 24

cytoplasmic receptors

Question 25

action of aldosterone

Answer 25

increases synthesis of a protein that activates ENaC and Na+/K+ATPase

Question 26

examples of potassium-sparing diuretics

Answer 26

spironolactone and eplerenone

Question 27

why do potassium-sparing diuretics have limited diuretic action?

Answer 27

modulated by aldosterone

Question 28

action of potassium-sparing diuretics

Answer 28

antagonists of aldosterone receptor so increase excretion of Na+ while decreasing excretion of K+

Question 29

action of amiloride and triamterene?

Answer 29

block luminal Na+ channels in collecting duct

Question 30

when are potassium-sparing diuretics contraindicated?

Answer 30

severe renal impairment hyperkalaemia Addison's

Question 31

example of osmotic diuretic

Answer 31

mannitol

Question 32

how do osmotic diuretics enter the filtrate?

Answer 32

glomerular filtration

Question 33

where do osmotic diuretics act?

Answer 33

PCT

Question 34

when are osmotic diuretics used?

Answer 34

acutely raised ICP and IOP | prevention of acute hypovolaemia in renal failure to maintain UO

Question 35

adverse of osmotic diuretics

Answer 35

transient expansion of blood volume | hyponatraemia

Question 36

examples of CA inhibitors

Answer 36

acetazolamide

Question 37

action of CA inhibitors

Answer 37

increase excretion of HCO3-

Question 38

when are CA inhibitors used?

Answer 38

glaucoma following eye surgery dysuria to prevent uric stones

Question 39

example of a vaptan

Answer 39

tolvaptan

Question 40

action of vaptans

Answer 40

competitive antagonists of ADH receptors which causes excretion of water without accompanying Na+ loss as it acts in the collecting duct

Question 41

when are vaptans used?

Answer 41

SIADH to correct hyponatraemia

Question 42

where is glucose reabsorbed in the nephron? and which transporter?

Answer 42

PCT by SGLT2

Question 43

when does glucose appear in the urine?

Answer 43

concentration exceeds threshold

Question 44

example of SGLT2i

Answer 44

empagliflozin

Question 45

action of SLGT2i

Answer 45

excretion of glucose | weight loss

Question 46

adverse of SGLT2i

Answer 46

genital bacterial and fungal infections

Question 47

prostaglandins in the kidneys

Answer 47

PGE2 | PGI2

Question 48

what do prostaglandins cause in the kidney?

Answer 48

vasodilation loss of Na+ allowing adaption to hypoperfusion and maintenance of UO

Question 49

action of NSAIDs

Answer 49

inhibit COX and precipitate ARF in patients with low GFR

Question 50

what is involved in the triple whammy effect?

Answer 50

ACEI/ARB (efferent vasodilation) diuretics NSAIDs (afferent vasoconstriction)

Question 51

how is uric acid formed?

Answer 51

catabolism of purines

Question 52

what predisposes to gout?

Answer 52

high urate in serum

Question 53

action of probenecid and sulfinpyrazole

Answer 53

block reabsorption of urate in PCT

Question 54

action of allopurinol

Answer 54

stops urate synthesis