SY 12-2 ACE INHIBITORS AND ARBS

Abstract

Blockade of the renin-angiotensin-aldosterone system (RAAS) can be accomplished at the level of the angiotensin-generating enzymes renin and angiotensin-converting enzyme (ACE; using renin inhibitors or ACE inhibitors), the type 1 angiotensin II (AT1) receptor or mineralocorticoid receptor (MR; using angiotensin receptor blockers [ARBs] or MR blockers) and/or renin release (using beta-blockers). Several of these drugs are often combined-for example in heart failure-but such approaches may ultimately lead to RAAS annihilation with adverse consequences such as hypotension, renal dysfunction and hyperkalaemia. The biochemical consequences of each type of blockade are different. For instance, ACE inhibitors will lower angiotensin II, thus no longer allowing stimulation of both AT1 and type 2 angiotensin II (AT2) receptors, while ARBs raise angiotensin II, allowing selective stimulation of the unoccupied AT2 receptor. This might be of particular importance in women, in whom the protective AT2 receptor pathway is believed to be upregulated. Multiple clinical trials have compared the various types of RAAS blockers and/or their combination. This talk will summarize the current evidence with regard to similarities and differences between ACE inhibitors and ARBs, also considering their side-effect profile, dose and combination with other RAAS blockers.