3.2 Diuretics

Question 1

natriuresis

Answer 1

process of sodium excretion in urine

Question 2

name 5 main classes of diuretics

Answer 2

1. carbonic anhydrase inhibitors
2. osmotic diuretics
3. loop diuretics
4. potassium sparing diuretics
5. thiazide (thiazide like) diuretics

Question 3

where do diuretics have their effects on carrier/transporters?

Answer 3

-luminal membrane
-renal tubular cells

Question 4

primary site for secretion of crate and creatinine

Answer 4

PCT

Question 5

location of osmotic diuretics

Answer 5

anywhere in nephron but mainly PCT (most water reabsorbed here)

Question 6

what type of diuretic is amiloride? where does it act?

Answer 6

carbonic anhydrase
late DCT/CD

Question 7

are SGLT-2 inhibitors diuretics?

Answer 7

no, but they do reduce Na+ absorption

Question 8

clinical uses of osmotic diuretics

Answer 8

-acute renal failure due to shock/trauma to maintain urine flow
-acute drug poisoning to eliminate drugs
-opthalmic/brain procedures to lower intracranial/intraocular pressure

Question 9

side effects of osmotic diuretics

Answer 9

-headache, nausea (hyponatraemia)
-compliocates heart failure due to extracellular volume expansion
-dehydration, hypernatraemia

Question 10

how do osmotic diuretics cause extracellular volume expansion? why’s this a problem in heart failure?

Answer 10

mannitol in blood so more water remains in plasma, not interstitium
blood volume increases
more pressure put on heart if person has heart failure

Question 11

speed of onset of loop diuretics

Answer 11

fast

Question 12

which emergency situations can loop diuretics help treat?

Answer 12

-hypercalcaemia
-acute pulmonary oedema
-acute hyperkalaemia
-acute hypercalcaemia
-severe oedema in congestive HF, nephrotic syndrome

Question 13

side effects of loop diuretics

Answer 13

-hypovolemia (potent so lose too music water)
-hyponatraemia
-hypokalaemia
-hypomagnesia
-hypocalcaemia
-metabolic alkalosis

Question 14

explain how loop diuretics can cause hypokalaemia

Answer 14

-more Na+ devivered to CD as less reabsorbed in LoH
-diffuses passively through ENaC
-must lose K+ from blood to CD cells to urine via ROMK (to balance charges)

Question 15

explain why the Na+Ca2+ exchanger is more active in DCT when thiazide diuretics are used?

Answer 15

Na+/Cl- exchanger blocked by diuretic, so less Na+ in cell so better gradient for Na+ to enter via Na+/Ca2+ exchanger

Question 16

effects of thiazide diuretics on excretion of:
1. NaCl
2. K+
3. Mg2+
4. Ca2+
5. uric acid

Answer 16

1. increase
2. increase
3. increase
4. decrease
5. decrease

Question 17

thiazide diuretics can be used for treatment of what?

Answer 17

-essential hypertension
-mild HF
-calcium nephrolithiasis
-osteoporosis
-nephrogenic diabetes insipidus

Question 18

first line anti hypertensive and why

Answer 18

thiazide diuretics
less potent

Question 19

name of the channel which enables excretion of K+

Answer 19

ROMK

Question 20

uses of potassium sparing and aldosterone antagonists diuretics

Answer 20

-secondary hyperaldosteronism
-CHF, cirrhosis, nephrotic syndrome
-hypertension

Question 21

potassium sparing and aldosterone antagonists diuretics are contraindicated in patients with….

Answer 21

-hyperkalaemia
-liver disease