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Angiotensin Receptor Blockers (ARB's)
Fichas del conjunto (4)
- 1Give eg's of & indications for ARB'seg's: losartan, candesartan, irbesartan
Indications: ARB's are generally used when ACEi's are not tolerated due to cough. The indications are the same:
• HT
• CHF
• Ischaemic HT disease
• Diabetic neuropathy
• CKD with proteinuria - 2MOA of ARB's.ARBs have similar effects to ACEi's, but instead of inhibiting the conversion of angiotensin I to angiotensin II, ARB's block the action of angiotensin II on the AT1 receptor. Angiotensin II is a vasoconstrictor & stimulates aldosterone secretion. Blocking its action reduces peripheral vascular resistance (afterload), which lowers BP. It particularly dilates the efferent glomerular arteriole, which reduces intraglomerular pressure & slows the progression of CKD. Reducing the aldosterone level promotes sodium & water excretion. This can help to reduce venous return (preload), which has a beneficial effect in HF.
- 3SE's of ARB's.• Hypotension
• Hyperkalaemia
• Renal failure - this is particularly relevant in patients with renal artery stenosis, who rely on constriction of the efferent glomerular arteriole to maintain glomerular filtration - 4CI's, cautions, & important interactions of ARB's.CI's:
• Renal artery stenosis
• AKI
Cautions:
• Pregnancy
• Breastfeeding
• CKD - lower dose & monitor carefully
Important interactions:
Due to the risk of hyperkalaemia, avoid prescribing ARBs with other potassium-elevating drugs, including potassium supplements (oral or IV) and potassium-sparing diuretics except under specialist advice for advanced HF. In combination with other diuretics they may be associated with profound first-dose hypotension. The combination of NSAID's with ARB's ^risk of renal failure.