Biotech Values

[rfj1862]

>Why spend more money for Exforge ?

It's my understanding that both Ace Inhibitors and Angiotensin Receptor Blockers prevent or block Angiotensen II<

I would have answered this sooner, but--strangely enough--I'm at a meeting for a new antihypertensive.

The answer is yes, you are perfectly correct. However, ACE inhibitors and ARBs block different steps in the cycle: ACE inhibitors prevent conversion of angiotensin I to angiotensin II by angiotensin-converting enzyme, and ARBs block the interaction between angiotensin II and the angiotensin II receptor. [As an aside, the direct renin inhibitors block the conversion of angiotensinogen to angiotensin I, the very first step of the cycle.]

So, the question is, why do you need an ARB when you can block production of angiotensin I in the first place? And, of course, with the advent of the direct renin inhibitors the question would be why do you need ACE inhibitors or ARBs at all when you can block the first step in the renin-angiotensin system?

The first answer is that nothing is 100%. In fact, it's been shown that when you combine various drugs that act on the renin -angiotensin system, you can get additional BP reductions. That is to say, you can put an ACE with an ARB, or a direct renin inhibitor with an ARB, and get additional BP-lowering efficacy. Why? I won't get into all the reasons for all of the steps, but one example is that there are non-ACE pathways for the conversion of angiotensin I to angiotensin II.

The second answer is that many patients do not tolerate ACE inhibitors well. ACE inhibitors are well-known for causing cough. Similarly, some patients do not tolerate ARBs well.

The third answer is that there's always room in the therapeutic toolkit for more and better-tolerated antihypertensive agents. JNC 7 recognizes the need for multiple antihypertensives to get to goal; in fact, studies show that patients need, on average, 2-3 agents to achieve their goal. And the more comorbid conditions patients have (eg, diabetes, renal disease, etc), the more antihypertensives they need to get to goal.

The fourth and fifth answers revolve around compliance and cost (I think Dew and I have already addressed this adequately).