pharmacology

Question 1

how do diuretics increase urine outflow

Answer 1

by inhibiting the resorption of electrolytes at various sites in the nephron

Question 2

when do diuretics enhance secretion of salt and water

Answer 2

in an increase of interstitial fluid causing tissue swelling

Question 3

what conditions causes oedema

Answer 3

• nephrotic syndrome
• congestive heart failure
• hepatic cirrhosis with ascites

Question 4

how do diuretics enter the filtrate

Answer 4

by either:

• glomerular filtration
• secretion via transport process in the proximal tubule

Question 5

what are the two transport systems

Answer 5

• the organic anion transporters

- the organic cation transporters

Question 6

what do organic anion transporters transport

Answer 6

acidic drugs

Question 7

what do organic cation transporters transport

Answer 7

basic drugs

Question 8

where do organic anions enter the cell

Answer 8

the basolateral membrane

Question 9

where do organic anions enter the lumen

Answer 9

apical membrane

Question 10

where do organic cations enter the cell

Answer 10

basolateral membrane

Question 11

where do organic cations enter the lumen

Answer 11

at the apical membrane

Question 12

what do loop diuretics do

Answer 12

inhibit the Na/K/2Cl transporter by binding to the Cl site

Question 13

where are loop diuretics absorbed

Answer 13

in the GI tract

Question 14

clinical indications of loop diuretics

Answer 14

to reduce salt and water overload associated with:

• chronic heart failure
• chronic kidney failure
• hepatic cirrhosis with ascites
• nephrotic syndrome

to increase urine volume in acute kidney failure
to treat hypertension
to reduce acute hypercalcaemia

Question 15

contraindications of loop diuretics

Answer 15

• severe hypovolaemia or dehydration
• severe hypokalaemia and/or hyponatraemia
• hepatic encephalopathy
• gout

Question 16

side effects of loop diuretics

Answer 16

• causing low electrolyte states
• hypovolaemia and hypotension
• hyperuricaemia
• dose-related loss of hearing

Question 17

what do thiazide diuretics do

Answer 17

inhibit the Na/Cl carrier by binding to the Cl site

Question 18

which mechanism do thiazide diuretics enter the nephron by

Answer 18

the OAT mechanism

Question 19

clinical indications for thiazide diuretics

Answer 19

• mild heart failure
• hypertension
• severe resistent oedema
• renal stones
• nephrogenic diabetes insipidus

Question 20

contraindications for thiazide diuretics

Answer 20

• hypokalaemia
• hyponatraemia
• gout

Question 21

adverse effects of thiazide diuretics

Answer 21

• hypokalaemia
• metabolic acidosis
• hypovolaemia and hypotension
• hypomagneasmia
• hyperuricaemia
• erectile dysfunction
• impaired glucose tolerance

Question 22

what type of drugs are amiloride, triamterene, spironolactone and eplerenone

Answer 22

potassium sparing diuretics

Question 23

what do amiloride and triamterene do

Answer 23

block the apical sodium channel and decrease sodium reabsorption

Question 24

what do spironolactone and eplerenone do

Answer 24

compete with aldosterone for binding to intracellular receptors

Question 25

what happens if potassium sparing diuretics are given alone

Answer 25

they cause hyperkalaemia

Question 26

what are aldosterone antagonists used for (spironolactone)

Answer 26

- heart failure - primary hyperaldosteronism - resistant essential hypertension - secondary hyperaldosteronism

Question 27

contraindications of potassium sparing diuretics

Answer 27

- severe renal impairment - hyperkalaemia - addisons disease

Question 28

what do osmotic diuretics do

Answer 28

increase the osmolality of the filtrate, opposing the absorption of water in parts of the nephron that are freely permeable to water

Question 29

where is the major site of action of osmotic diuretics

Answer 29

the proximal tubule

Question 30

clinical uses of osmotic diuretics

Answer 30

- prevention of acute hypovolaemia renal failure to maintain urine flow - urgent treatment of acutely raised intracranial and intraocular pressure

Question 31

adverse effects of osmotic diuretics

Answer 31

transient expansion of blood volume and hyponatraemia

Question 32

what do carbonic anhydrase inhibitors do

Answer 32

increase excretion of HCO3 with Na, K and H2O, alkalinising the urine

Question 33

what are carbonic anhydrase inhibitors used for

Answer 33

- glaucoma and following eye surgery - prophylaxis of altitude sickness - infantile epilepsy

Question 34

what can alkalinising the urine be useful in

Answer 34

- relief of dysuria - prevention of crystallization of weak acids - enhancing the excretion of weak acids

Question 35

what happens at the kidneys when aldosterone is secreted from the adrenal cortex

Answer 35

enhanced tubular sodium reabsorption and salt retention

Question 36

what happens at the kidneys when vasopressin is secreted from the posterior pituitary

Answer 36

enhanced water reabsorption

Question 37

what causes neurogenic diabetes insipidus

Answer 37

lack of vasopressin secretion from the posterior pituitary

Question 38

what causes nephrogenic diabetes insipidus

Answer 38

inability of the nephron to respond to vasopressin

Question 39

what can the act of vasopressin on the kidney be inhibited by

Answer 39

- lithium - demeclocycline - vaptans

Question 40

what is Tolvaptan used in

Answer 40

SIADH to correct hyponatraemia

Question 41

where is SGLT1 found

Answer 41

kidneys and intestine

Question 42

where is SGLT2 found

Answer 42

proximal tubule of the kidneys

Question 43

what does inhibition of SGLT2 result in

Answer 43

glucosuria

Question 44

what do SGLT2 inhibitors cause

Answer 44

- excretion of glucose - decreases in HbA1c - weight loss

Question 45

what prostaglandins are synthesised by the kidneys

Answer 45

PGE2 | PGI2

Question 46

how do prostaglandins affect GFR

Answer 46

- a direct vasodilator effect upon the afferent arteriole - releasing renin leading to increased levels of angiotensin II that vasoconstricts the efferent arteriole - filtration pressure increases

Question 47

what is the 'triple whammy' (three drugs that combined could have detrimental effects)

Answer 47

ACEI (or ARB), diuretic and NSAID

Question 48

what do uricosuric agents do

Answer 48

used in treatment of gout by blocking reabsorption of urate in the proximal tubule

Question 49

side effect of diuretics

Answer 49

gout