ANGIOTENSIN RECEPTOR BLOCKERS

Question 1

ARBs - examples

Answer 1

Losartan
Candesartan
Irbesartan

Question 2

ARBs - indications

which drug does it have the same indications as?

Answer 2

Hypertension

Chronic heart failure

Ischaemic heart disease - reduce risk of CV events (e.g.- MI, stroke)

Diabetic nephropathy and chronic kidney disease with proteinuria

(same as ACEi)

Question 3

A patient has been given Ramipril to manage their hypertension - they come to the GP complaining of a persistent annoying cough - what do you do?

Answer 3

Switch to ARBs

ARBs are generally used when ACEi not well tolerated due to cough

Question 4

Why does ramipril cause a dry cough but not losartan?

Answer 4

Losartan (ARB) does NOT inhibit ACE and therefore does not affect bradykinin metabolism

For this same reason, ARB is also less likely to cause angioedema

Question 5

ARBs - MOA in HTN

Answer 5

Block the action of ATII on the AT1 receptors (on VSMCs)

This blocks ATII vasoconstrictor effect = reduces afterload = lowers BP

Question 6

ARBs - MOA in heart failure

Answer 6

Block the action of ATII on the AT1 receptors (on VSMCs)

ATII also stimulates aldosterone secretion
Blocking ATII = reduce aldosterone levels = promotes Na+/H2O excretion = reduce preload = beneficial in HF

Question 7

ARBs - adverse effects

Answer 7

→Hypotension (especially after first dose)

→Hyperkalaemia

→Renal failure

Question 8

ARB- Contraindications (do not use in)

Answer 8

DO NOT USE:

1) Renal Artery Stenosis
2) Acute Kidney Injury
3) Pregnant women (or likely to become)
4) Breastfeeding Women

Question 9

Important interactions

Answer 9

K+ ELEVATING DRUGS
1) Do not use with Potassium elevating / sparing drugs

NSAIDS
2) Combination with NSAIDs increases NEPHROTOXICITY