ARBs
Angiotensin II receptor blockers
| Class / Subclass / Drug (brand name) | Usual Dose Range, mg / day | Daily Frequency |
| Candesarran (Atacand) | 8-32 | 1 or 2 |
| Eprosartan (Teveten) | 600-800 | 1 or 2 |
| Irbesartan (Avapro) | 150-300 | 1 |
| Losarran (Cozaar) | 50-100 | 1 or 2 |
| Olmesartan (Benicar) | 20-40 | 1 |
| Telmisartan (Micardis) | 20-80 | 1 |
| Valsartan (Diovan) | 80-320 | 1 |
Angiotensin II is generated by the renin-angiotensin pathway (which involves ACE) and an alternative pathway that uses other enzymes such as chymases. ACE inhibitors block only the renin-angiotensin pathway, whereas ARBs antagonize angiotensin II generated by either pathway. The ARBs directly block the angiotensin type 1 receptor that mediates the known effects of angiotensin II (vasoconstriction, aldosterone release, sympathetic activation, antidiuretic hormone release, and constriction of the efferent arterioles of the glomerulus).
Unlike ACE inhibitors, ARBs do not block the breakdown of bradykinin. While this accounts for the lack of cough as a side effect, there may be negative consequences because some of the antihypertensive effect of ACE inhibitors may be due to increased levels of bradykinin. Bradykinin may also be important for regression of myocyte hypertrophy and fibrosis, and increased levels of tissue plasminogen activator.
All drugs in this class have similar antihypertensive efficacy and fairly flat dose-response curves. The addition of low doses of a thiazide diuretic can increase efficacy significantly.
In patients with type 2 diabetes and nephropathy, ARB therapy has been shown to significantly reduce progression of nephropathy. For patients with LV dysfunction, ARB therapy has also been shown to reduce the risk of CV events when added to a stable regimen of a diuretic, ACE inhibitor, and j8-blocker or as alternative therapy in ACE inhibitor-intolerant patients.
ARBs appear to have the lowest incidence of side effects compared with other antihypertensive agents. Because they do not affect bradykinin, they do not cause a dry cough like ACE inhibitors. Like ACE inhibitors, they may cause renal insufficiency, hyperkalemia, and orthostatic hypotension. Angioedema is less likely to occur than with ACE inhibitors, but cross-reactivity has been reported. ARBs should not be used in pregnancy.
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