Diuretics

Question 1

What are the main physiological roles of kidneys

Answer 1

Regulation: Fluid, electrolytes, acid base
Excretion: metabolites, Drugs
Endocrine: renin, Erythropoietin
Metabolism: Vitamin D, insulin, PTH

Question 2

What are the types of commonly used diuretics

Answer 2

Loop
Thiazide
K sparing diuretics
Aldosterone antagonists

Question 3

What are types of rarely used diuretics

Answer 3

Carbonic anhydrase inhibitors
Osmotic diuretics
ADH antagonists

Question 4

What are Drugs that have diuretic-like effects

Answer 4

Digoxin

Amiloride

Question 5

What is mechanism of action of carbonic anhydrase inhibitors

Answer 5

Inhibit carbonic anhydrase at PCT

Inhibit Na reabsorption

Question 6

What are side effects of carbonic anhydrase inhibitors

Answer 6

Metabolic acidosis (bicarb loss) 
Hypokalaemia

Question 7

What is Carbonic anhydrase inhibitors indicated

Answer 7

Glaucoma

Question 8

What is mechanism of action of osmotic diuretics

Answer 8

Freely filtered and poorly reabsorbed
Increases filtrate osmolality
Draws water into filtrate down osmotic gradient

Question 9

When is osmotic diuretics indicated

Answer 9

Cerebral oedema

Pulmonary oedema

Question 10

What are side effects of osmotic diuretics

Answer 10

Hypovolaemia

Hypernatraemia

Question 11

What is mechanism of action of ADH Antagonists

Answer 11

Inhibit ADH receptors at DCT and CD

Inhibit water reabsorption

Question 12

What are types of ADH antagonists

Answer 12

Lithium

Demeclocycline

Question 13

What is mechanism of action of digoxin

Answer 13

Inhibit Na/K+ ATPase

Question 14

When is digoxin indicated

Answer 14

Atrial fibrillation

Has a mild diuretic effect

Question 15

Give examples of loop diuretics

Answer 15

Furosemide

Bumetanide

Question 16

What is mechanism of action of Loop diuretics

Answer 16

Inhibit NKCC2 co transporter at thick ascending limb
Inhibit Na reabsorption (25%)
Inhibit K reabsorption

Question 17

When is loop diuretics indicated

Answer 17

Heart failure

Liver failure

Question 18

What are side effects of loop diuretics

Answer 18

Hypokalaemia
Hypokalaemic metabolic alkalosis
Ototoxicity

Question 19

What are drug interactions with loop diuretics

Answer 19

Aminoglycosides: ototoxicity, nephrotoxicity
Steroids: hypokalaemia
Digoxin: hypokalaemia, digoxin toxicity

Question 20

Give examples of thiazide diuretic s

Answer 20

Bendroflumethiazide

Thiazide-like diuretics: chlortalidone, metolazone

Question 21

What is mechanism of action of thiazide diuretics

Answer 21

Inhibit NaCl co transporter at DCT
Inhibit Na reabsoprtion

Decreased Ca excretion
Decreased Uric acid excretion

Question 22

What are indications of thiazide diuretics

Answer 22

Hypertension
Heart failure
Kidney stones

Question 23

What are side effects of thiazide diuretics

Answer 23

Hypokalaemia
Hyponatraemia
Hypercalcaemia
Hyperuricaemia
Gout 
Erectile dysfunction

Question 24

What are drug interactions of thiazide diuretics

Answer 24

Steroids
Digoxin
Beta blockers - hyperglycaemia, hyperlipidaemia
Carbemazepine - hyponatraemia

Question 25

What are types of K sparing diuretics

Answer 25

Amiloride | Aldosterone antagonists

Question 26

What is mechanism of action of amiloride

Answer 26

Inhibit ENaC at DCT + CD Inhibit Na reabsorption (2%) Inhibit ROMK activity Reduce K excretion

Question 27

When is amiloride indicated

Answer 27

Add-on therapy to K-losing diuretics

Question 28

What are drug interactions with amiloride

Answer 28

Ace-inhibitors: Hyperkalaemia

Question 29

Give examples of aldosterone antagonists

Answer 29

Spironolactone | Eplerenone

Question 30

What is mechanism of action of spironolactone

Answer 30

Inhibit aldosterone binding to Mineralocorticoid receptors at DCT + CD Inhibit Na/K ATPase and ENaC synthesis Inhibit Na reabsorption Reduce K excretion

Question 31

When is spironolactone indicated

Answer 31

Hypertension Heart failure Liver failure Hyperaldosteronism

Question 32

What are side effects of spironolactone

Answer 32

Gynaecomastia | Hyperkalaemia

Question 33

What are the general side effects of diuretics

Answer 33

Hypersensitivity - Anaphylaxis, rash Hypovolaemia, postural hypotension Electrolyte imbalance Metabolic disturbance

Question 34

What are causes of diuretic resistance

Answer 34

``` Patient in compliance High Na intake Volume depletion NSAID Incomplete treatment of primary disorder ```

Question 35

What are issues of prescribing drugs in renal disease

Answer 35

Drug Nephrotoxicity | Accumulation of drugs to toxic levels

Question 36

What are prescribing rules in renal disease

Answer 36

Avoid nephrotoxins Monitor U+Es and renal function Use lower dose according to GFR

Question 37

Give examples of nephrotoxic drugs

Answer 37

``` Ace inhibitors NSAIDs Aminoglycosides Penicillin Metformin ```

Question 38

What are prescribing rules in the elderly with renal disease

Answer 38

Renal function overestimated Start at low dose, titrate slowly Polypharmacy is common Cautious of DDIs