Diuretics

Question 1

What are the two types of oedema?

Answer 1

Pulmonary - lungs (SOB)
Peripheral - extremities (ankle swelling)

Question 2

Examples of thiazide diuretics

Answer 2

Bendroflumethiazide
Indapamide
Chlortalidone
Metolazone

Question 3

Mechanism of action of thiazide diuretics

Answer 3

Inhibit sodium reabsorption at the beginning of the distal convoluted tubule

Question 4

When would thiazide diuretics be used?

Answer 4

Relieve oedema due to chronic heart failure
Reduce blood pressure

Question 5

How long do the effects of thiazide diuretics last?

Answer 5

24 hours - so should be taken in the morning to avoid sleep disturbances and falls during the night

Question 6

Which thiazide diuretic can be given on alternate days?

Answer 6

Chlortalidone as it has a longer duration of action

Question 7

Onset of action of thiazide diuretics

Answer 7

1-2 hours

Question 8

Which thiazide diuretic is preferred for the management of hypertension?

Answer 8

Chlortalidone and indapamide

Question 9

Which thiazide diuretic is less associated with metabolic disturbances and aggravation of diabetes?

Answer 9

Indapamide

Question 10

Mechanism of action of loop diuretics

Answer 10

Inhibit reabsorption from the ascending limb of the loop of Henle

Question 11

Onset of action of loop diuretics

Answer 11

1 hour oral and 30 minutes IV

Question 12

Examples of loop diuretics

Answer 12

Furosemide
Bumetanide
Torsemide

Question 13

When would a loop diuretic be used?

Answer 13

Pulmonary oedema due to left ventricular failure
Manage heart failure symptoms
If prone to waking up in the night needing to go to the toilet

Question 14

How long do the effects of a loop diuretic last?

Answer 14

6 hours so can be given twice daily without interfering with sleep

Question 15

Side effects of thiazide and loop diuretics

Answer 15

Hyponatraemia
Hypomagnesaemia
Hypokalaemia
Exacerbate diabetes and exacerbate gout (hyperglycaemia less likely with loop and gout only with thiazide)
Hypotension

Question 16

Examples of potassium-sparing diuretics

Answer 16

Spironolactone
Eplerenone
Amiloride
Triamterene

Question 17

Specific side effect of triamterene

Answer 17

Blue urine

Question 18

Mechanism of action of of potassium-sparing diuretics

Answer 18

Prevent sodium reabsorption in the distal tubule collecting duct

Question 19

Side effects of potassium sparing

Answer 19

Hyperkalaemia
Change in libido
Breast pain or tenderness

Question 20

What should not be taken alongside potassium sparing and MRAs?

Answer 20

Potassium supplements
Concurrent use of ACE-I / ARBs is cautioned due to risk of severe hyperkalaemia

Question 21

Examples of aldosterone antagonists

Answer 21

Spironolactone
Eplerenone

Question 22

Mechanism of action of aldosterone antagonists

Answer 22

Inhibits potassium secretion in the distal tubule collecting duct

Question 23

When should an aldosterone antagonist be stopped?

Answer 23

If person becomes dehydrated due to vomiting and/or diarrhoea

Question 24

Diuretics interactions

Answer 24

Loop and thiazide: hypokalaemia inducing drugs

Potassium sparing: hyperkalaemia inducing drugs

Loop diuretics + aminoglycosides: nephrotoxicity and ototoxicity

Spironolactone / loop + lithium: reduce lithium secretion = raise levels of lithium = toxicity

Question 25

When would spironolactone be the preferred diuretic?

Answer 25

Treatment of oedema and ascites caused by cirrhosis of the liver
Furosemide can be used as an adjunct
Primary hyperaldosteronism

Question 26

What is eplerenone licensed for use in?

Answer 26

As an adjunct in left ventricular dysfunction with evidence of heart failure post mI
Chronic mild heart failure with LVEF

Question 27

Which diuretic is used to treat cerebral oedema and raised intra-ocular pressure?

Answer 27

Manntiol