Diuretics

Question 1

What are the functions of the kidney?

Answer 1

Regulatory
Excretory
Endocrine
Metabolism

Question 2

What drugs act on the renal tubules?

Answer 2

Carbonic anhydrase inhibitors
Osmotic diuretics
Loop diuretics
Thiazides
K+ sparing diuretics
Aldosterone antagonists
ADH antagonists

Question 3

Where do carbonic anhydrase inhibitors work?

Answer 3

PCT

Question 4

How do carbonic anhydrase inhibitors work?

Answer 4

Prevent reuptake of sodium bicarb and water

Question 5

What are carbonic anhydrase inhibitors generally used to treat?

Answer 5

Glaucoma

Question 6

What are the carbonic anhydrase inhibitors?

Answer 6

Acetazolamide and dorzolamide

Question 7

What are the ADRs associated with carbonic anhydrase inhibitors?

Answer 7

Metabolic acidosis and hypokalaemia

Question 8

Name an osmotic diuretic.

Answer 8

Mannitol

Question 9

Where do osmotic diuretics work?

Answer 9

The PCT and descending loop of Henle

Question 10

What are the ADRs associated with osmotic diuretics?

Answer 10

Excessive water loss and hypernatraemia

Question 11

Where do loop diuretics work?

Answer 11

Thick ascending loop of Henle

Question 12

Name some loop diuretics.

Answer 12

Furosemide

Bumetamide

Question 13

How do loop diuretics work?

Answer 13

Inhibit NaCl reabsorption - very potent as major site of water reabsorption

Question 14

What are the ADRs associated with loop diuretics?

Answer 14

Hypokalaemia

Concurrent Ca2+ and Mg2+ excretion

Question 15

What are examples of thiazide diuretics?

Answer 15

Metolazone
Indapamide
Others ending in -thiazide

Question 16

Where do thiazide diuretics work?

Answer 16

DCT

Question 17

How do thiazide diuretics work?

Answer 17

Inhibit NaCl reabsorption and promotes Ca2+ reabsorption

Question 18

What are the ADRs associated with thiazide diuretics?

Answer 18

Hypokalaemia
Hyperuricaemia
Hypercalcaemia

Question 19

Where do aldosterone antagonists work?

Answer 19

Collecting ducts

Question 20

Name the aldosterone antagonists.

Answer 20

Spironalactone

Eplerenone

Question 21

What is good about aldosterone antagonists?

Answer 21

There are K+ sparing

Question 22

How do ADH antagonists work?

Answer 22

(Aside from the obvious) Reduce the ability of the collecting ducts to concentrate urine.

Question 23

Name some ADH antagonists.

Answer 23

Lithium

Demeclocycline

Question 24

Name 2 other drugs with diuretic activity.

Answer 24

Digoxin

Amiloride

Question 25

How is digoxin diuretic in nature?

Answer 25

Inhibits tubular Na+K+ ATPase

Question 26

How is amiloride diuretic in nature?

Answer 26

Inhibits Na+ channels in DCT and CD. K+ sparing, so good adjunct

Question 27

What general ADRs should we be aware of for diuretics?

Answer 27

``` Anaphylaxis/rash (rare) Hypovolaemia and hypotension Acute renal failure (due to above) Electrolyte disturbance Metabolic disturbance ```

Question 28

What are the common ADRs specific to thiazides?

Answer 28

Gout | Erectile dysfunction

Question 29

What are the ADRs specific to furosemide?

Answer 29

Ototoxicity (rare)

Question 30

What is the ADR specific to bumetanide?

Answer 30

Myalgia

Question 31

What are the common ADRs specific to spironolactone?

Answer 31

Hyperkalaemia | Painful gynaecomastia

Question 32

Which diuretics interact with ACE inhibitors, and how?

Answer 32

K+ sparing diuretics to cause hyperkalaemia -> cardiac problems

Question 33

Which diuretics interact with aminoglycosides (e.g. gentamicin), and how?

Answer 33

Loop diuretics to cause ototoxicity and nephrotoxicity

Question 34

Can digoxin be added onto a thiazide and a loop diuretic?

Answer 34

No as Loop + thiazide can cause hypokalaemia which can precipitate digoxin toxicity

Question 35

What group of drug increases the risk of hypokalaemia when taken alongside thiazides or loop diuretics?

Answer 35

Steroids

Question 36

What happens if i mix a beta blocker and a thiazide?

Answer 36

Hyperglycaemia Hyperlipidaemia Gout (via hyperuricaemia)

Question 37

Thiazide + what = increased risk of hyponatraemia?

Answer 37

Carbamazepine

Question 38

Can diuretic resistance occur?

Answer 38

Yes

Question 39

How can diuretic resistance occur iatrogenically?

Answer 39

Incomplete treatment of the primary disorder NSAIDs Volume depletion

Question 40

How can diuretic resistance occur due to patient factors?

Answer 40

Continued high dietary Na+ intake Poor compliance Volume depletion

Question 41

What are the 3 major indications for diuretic use?

Answer 41

Heart Failure Hypertension Decompensated Liver Disease

Question 42

Which diuretics do we use for heart failure?

Answer 42

Loop and thiazides | Spironalactone (not for diuretic effect)

Question 43

Which diuretics do we use for hypertension?

Answer 43

Thiazides Spironalactone Loop

Question 44

Which diuretics do we use for decompensated liver disease?

Answer 44

Spironolactone for managing oedema | Loop diuretics

Question 45

How do we prescribe in renal failure?

Answer 45

Avoid nephrotoxins as much as possible. | Decrease dosage in line with eGFR if metabolised by or excreted via the kidneys.

Question 46

What is more likely to occur in renal failure?

Answer 46

Hyperkalaemia

Question 47

Describe the identification and management of hyperkalaemia.

Answer 47

Bloods and ECG to diagnose Treat with calcium gluconate, insulin (+dextrose), calcium resonium, sodium bicarb, and salbutamol. Identify the cause and treat

Question 48

How does hyperkalaemia show on an ECG?

Answer 48

Tall tented T waves (V4-V6) Fewer P waves Widened QRS complexes