ARB's

Question 1

What are ARBs (Angiotensin II receptor blockers) used for?

Answer 1

Used in HT, HF and post MI, when ACE-I ineffective or not tolerated
Also used in diabetic nephropathy

Question 2

What is the most common side effect on an ARB?

Answer 2

Dry cough- likely due to bradykinin accumulation secondary to reduced ACE action- second line ARBs if intolerant of cough

Question 3

What is the mechanism of action of ARBs?

Answer 3

Selectively inhibit ATII at receptor site- binding of it at AT1 site: causes VC, release of aldosterone, sympathetic activation and other CV effects
Causes Vasodilation and blockage of aldosterone release

Question 4

Contra-indications of ARBs

Answer 4

Aliskiren- direct renin inhibitor (if eGFR below 60ml/min/1.73m2)
Combination of ARB’s with aliskiren contraindicated in DM

Question 5

What groups are at risk with ARBs?

Answer 5

• Afro-caribbean with LV hypertrophy may not benefit
• Aortic/mitral stenosis
• Elderly (start low dose)
• hypertrophic cardiomyopathy
• history of angioedema
• primary aldosteronism (may not benefit)
• renal artery stenosis

Question 6

Interactions

Answer 6

• ACEi’s
• Aliskiren
• Ciclosporin
• Diuretics
• K+ sparing diuretics/ aldosterone antagonists
• Lithium
• Potassium salts
  Hyperkalaemia, angioedema, sympomatic HT (incl. dizziness, esp w/ intravascular volume depletion like in diuretics)

Question 7

Pregnancy and breastfeeding

Answer 7

• Avoid unless essential- may be teratogenic, affecting foetal/neonatal blood pressure control and rental function, skull defects and oligohydramnios ( too little amniotic fluid) have been reported
• Limited data but generally not recommended

Question 8

Renal impairment

Answer 8

use with caution, low and slow

Question 9

Monitoring

Answer 9

Monitor plasma k+ concentration, especially in elderly and in renal impairment&raquo_space; hyperkalaemia