Ok...what is Extensive Hepatic Enzyme Inhibition?
It sounds scary and I can't find anything about it when I google it....
Like Piper said, there is a class of enzymes in the liver (hepatic) that metabolize various substances. There is a specific class of them which are referred to as the CYP 450 class, and within that class there are several enzymes that are very common in metabolizing (breaking down, changing, etc) drugs. Kava inhibits CYP 3A4 to a high degree according to this study:
http://dmd.aspetjournals.org/content/30/11/1153.long
Oh, and as far as kava being used for W/Ds from benzos... It's a bit complicated. We don't exactly know how kava works (completely), but we have a good idea. You can check out the "
How It Works" thread to get some idea if you are curious.
Needless to say, it helps through modulating ion channels (which have been shown to have a stabilizing psychoactive effect) as well as (my hypothesis, as well as some others)
upregulating GABA receptors.
Basically, I hypothesize that the gabaergic-like effects we experience could be due to kava indirectly effecting GABA receptors by (basically) creating more, or increasing the ability of endogenous and external substances to bind to GABA receptors. For example, the tolerance/dependence we experience with drugs like benzos is caused by what's called "downregulation" of GABA receptors which (basically) means that there become less receptors on the surface of the neuron meaning that there is essentially less ability for GABA (or drugs that affect GABA, like benzos) to have any GABA-like effect.
Sorry, don't mean to over-complicate it but I wanted to try to answer your question best I could!
Feel free to add your experiences to that thread BTW!