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Originally Posted by CASSIEBEL
Do you know if one, (ARB or ACEI) works better than the other when combined with a diuretic?
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I would expect similar results. However, from a purely scientific point of view, it would seem logical that the ARB might show more of a dependency on a diuretic (or low sodium diet) than the ACEI. This is probably splitting hairs. But, the reason I would make that guess is that an ACEI has another mechanism by way of increasing bradykinin levels. This also helps reduce BP slightly - though, this is not as significant as reducing ang II. However, bradykinin is a two edged sword as it also causes the cough.
Also, Lenin brought up a very good point. There is a lot of scientific evidence that the non-ACE pathways can actually cause ang II levels to return to normal over time. Thus, the potency of the ACEI can degrade. I should also add that there is another pathway called "tissue plasminogen activator" (tPA) that can also convert directly from angiotensinogen straight to ang II - bypassing renin, ang I and ACE altogether.
In the next couple years, we'll get yet another class called "Renin Inhibitors" (RI). The initial trials are showing these to have very good side-effect profiles (similar to ARBs). This should take care of the chymase pathway. But, it won't do anything for the tPA. I suspect the ideal future combo will be a RI + ARB. Though expensive, this should provide a near 100% blockage with virtually no side-effects.
Today, the ACE + ARB combo is very potent. But, side-effects can get out of hand - bradykinin levels get even higher. Speaking of which, there is another class called vasopeptidase inhibitors (aka. Super ACEI). While they are very potent, they have similar problems to the ACE + ARB combo. So much so, the FDA most likely will never approve this class.
Oh well... I need to stop. I am getting carried away here.
Pal