Are renin inhibitors the next big weapon in the fight against hypertension?
As we all know, ACE-I's & ARB's have so many renoprotective effects that there is substantial evidence towards using these medications as first-line agents for blood pressure management in those with kidney disease, diabetes, or proteinuria. In addition to blockade of angiotensin converting enzyme (ACE) or the angiotensin receptor (ARB), a new class of direct renin inhibitors of which aliskiren is the current prototype are now being tested. While the evidence here is still accumulating, the available data suggests that it gives similar decreases in BP when compared to ACE or ARB, and the results of the recent AVOID trial demonstrate that in patients already treated with ARB, addition of aliskiren compared to placebo led to significant reductions in the degree of proteinuria. It makes sense that inhibition of renin (the protein structure of which is illustrated above) would be an effective pharmacologic target of the renin-angiotensin system given that this, not angiotensin converting enzyme-catalyzing of angiotensin I to angiotensin II, is the rate-limiting step in the pathway.