PHARM: Diuretics

Question 1

loop diuretics
- MOA
- indications
- A/Es
- e.g.

Answer 1

• block Na/K/Cl pump to inhibit Na+/H2O reabsorption in thick ascending loop of Henle
• indications: HTN, HFrEF, oedema
• A/Es: hypotension, hypokalaemia (non-K+ sparing = increased digoxin toxicity + arrhythmia), hypovolaemia, hearing loss, hypocalcaemia, hypomagnesaemia, hyeruricaemia
• e.g. furosemide (end in -ide)

Question 2

thiazide diuretics
- MOA
- indications
- A/Es
- C/I

Answer 2

• inhibits NaCl pump = decreased Na+/H2O reabsorption @ DCT (less potent than loop)
• indications: milder HTN + HFrEF + oedema
• A/Es: hypotension (decreased CO), hypokalaemia (non-K+ sparing = increased digoxin toxicity + arrhythmia), hypercalcaemia, hyperuricaemia, hypomagnesaemia, hyperglycaemia, hypercholesterolaemia
• C/I: pregnancy

Question 3

aldosterone antagonists
- MOA
- indications
- A/Es
- e.g.

Answer 3

• inhibits action of aldosterone on mineralocorticoid receptor = decreased expression of Na+/K+ ATPase pump in basolateral membrane @ DCT/CD = increased Na+/H2O excretion (weak diuretic)
• also blocks the ECM deposition function of aldosterone which can prevent cardiac fibrosis
• indications: HTN, HFrEF, used with loop/thiazide diuretics to prevent hypokalaemia
• A/Es: hyperkalaemia (K+ sparing - arrhythmia), gynaecomastia (androgen inhibitor)
• e.g. spironolactone (end in -one)

Question 4

Na+ channel blockers (renal)
- MOA:
- indications
- A/Es

Answer 4

• MOA: inhibits Na+ channels in DCT = K+ sparing diuretic
• indications: HTN, aldosteronism, commonly used w/ thiazides/loops to prevent hypokalaemia
• A/Es: hyperkalaemia (K+ sparing - arrhythmia)

Question 5

osmotic diuretics
- MOA
- indication
- e.g.

Answer 5

• decreases Na+/H2O reabsorption in whole nephron
• LOCALISED oedema (e.g. glaucoma, increased intracranial pressure), NOT for generalised oedema b/c not enough Na+ excreted
• e.g. mannitol

Question 6

sodium-glucose cotransporter 2 (SGLT2) inhibitors
- MOA
- indications
- A/Es
- e.g.

Answer 6

• prevent reabsorption of glucose in PCT = decreased BP and BGL
• indications: T2DM with risk of CKD, CHF or atherosclerotic CVD
• A/Es: heavy glycosuria (increased risk of UTI/candidiasis), hypotension, weight loss, risk of hypoglycaemia (when combined with sulfonurea or insulin)
• e.g. dapagliflozin

Question 7

triple whammy medication

Answer 7

• RAAS inhibitor (ACE inhibitor/ARB), NSAID, diuretic
• NSAIDs decrease afferent flow, RAAS inhibitors increase efferent flow
• potential for renal failure in elderly/high risk Pts