Diuretics

Question 1

How do Carbonic Anhydrase Inhibitors work?

Answer 1

Prevent Na+/HCO3- reabsorption.

Question 2

When are carbonic anhydrase inhibitors used?

Answer 2

Glaucoma

Question 3

What is the ADR of carbonic anhydrase inhibitors?

Answer 3

Metabolic acidosis

Question 4

Name an Osmotic Diuretic and it’s route of administration

Answer 4

Mannitol, given intravenously

Question 5

When are osmotic diuretics used?

Answer 5

Raised intra-cranial pressure.

Question 6

What are contra-indications of osmotic diuretics?

Answer 6

Congestive heart failure and pulmonary oedema

Question 7

How do osmotic diuretics work?

Answer 7

Enter the tubules and as they are non-reabsorbable, water uptake is decreased.

Question 8

What are ADRs of osmotic diuretics?

Answer 8

Fever and chills

Question 9

How do loop diuretics work?

Answer 9

Inhibits NKCC2 transporter at the thick ascending limb, reducing sodium and thus water reabsorption.

Question 10

Name 3 loop diuretics

Answer 10

Furosemide, Torsemide, Bumetanide

Question 11

What is a loop diuretic contraindication?

Answer 11

Severe renal impairment

Question 12

What is the oral onset time of loop diuretics?

Answer 12

4-6 hour onset.

Question 13

When are loop diuretics used?

Answer 13

Oliguria, hypertension pulmonary oedema and heart failure.

Question 14

What are some ADRs of loop diuretics?

Answer 14

Hyponatraemia, hypokalaemia, hypovolaemia, hypotension, metabolic alkalosis, hyperuricaemia, ototoxicity (furosemide only) and myalgia (bumetanide only).

Question 15

What are 3 DDIs of loop diuretics?

Answer 15

Hypokalaemia with either cardiac glycosides or steroids, and ototoxicty with gentamicin.

Question 16

How do thiazide diuretics work?

Answer 16

Inhibit the Na/Cl co-transporter in the distal convoluted tubule, reducing sodium and subsequently water reabsorption.

Question 17

What are some contraindications of thiazide diuretics?

Answer 17

Hypokalaemia, hyponatraemia and hypercalcaemia.

Question 18

What are some ADRs of thiazide diuretics?

Answer 18

Hyporkalaemia, hyponatraemia, hypercalcaemia, hyperuricaemia, hypermagnesaemia, metabolic alkalosis and decreased glucose tolerance.

Question 19

Name 2 thiazide diuretics

Answer 19

Bendroflumethiazide and Metolazone

Question 20

Name 4 DDIs of thiazide diuretics

Answer 20

Increased hyponatraemia risk with carbamezipine, increased digoxin toxicity risk with digoxin, increased hypokalaemia risk with steroids, and increased hyperuricaemia and hyperglycaemia risk with beta-blockers.

Question 21

Name 2 potassium sparing diuretics

Answer 21

Amiloride and spironolactone

Question 22

How does amiloride work?

Answer 22

Blocks ENaC channels at the collecting ducts, reducing sodium and subsequently water intake.

Question 23

How does spironolactone work?

Answer 23

It is an aldosterone antagonist, reducing sodium secretion and causing diuresis.

Question 24

What are the two main ADRs of potassium sparing diuretics?

Answer 24

Hyperkalaemia and hyponatraemia.

Question 25

What are 3 additional ADRs for spironolactone?

Answer 25

Gynaecomastia, menstural disorder and erectile dysfunction.

Question 26

What is a DDI of potassium sparing diuretics?

Answer 26

ACE inhibitors, as it greatly increases the risk of hyperkalaemia.

Question 27

Name 2 ADH Antagonists

Answer 27

Lithium and Demecocylcine

Question 28

What effect does antagonising ADH have?

Answer 28

Reduces aquaporin-2 insertion into the cells of the collecting duct.

Question 29

What 3 things can cause poor diuresis?

Answer 29

High salt/sodium intake, NSAID use (lowers renal perfusion), and volume depletion.

Question 30

What 4 ECG changes indicate hyperkalaemia?

Answer 30

Tall tented T waves, prolonged PR interval, wide QRS complex and ST segment depression.

Question 31

What is given to protect the heart in hyperkalaemia?

Answer 31

Intravenous calcium gluconate.