Posted by Elizabeth on April 4, 2002, at 22:08:53
In reply to Re: CHRISTOPH: More about MAOI's!, posted by djmmm on April 3, 2002, at 7:04:13
> As far as I know Parnate is also an irreversible MAOI.
Yeah, that's my understanding too. Irreversible enzyme inhibition just means that the drug interacts with the enzyme (here, MAO) in such a way that the enzyme is effectively "destroyed," as opposed to competitive or reversible inhibitors, which tack onto the enzyme but can be displaced by other substrates if high enough concentrations (of the other substrate, that is) are present. I'm not very up on biochemistry, but I believe that the "bond" formed isn't an ordinary covalent bond -- enzymes like MAO are big, complicated molecules that interact in big, complicated ways. (Nardil and Parnate themselves are pretty simple though -- both of them are very similar to amphetamine.)
Irreversible enzyme inhibitors are also sometimes called "suicide inhibitors," which is either very appropriate or in very poor taste (I can't decide which) when applied to an antidepressant.
> Parnate has a rather short half life, but active metabolites, and these active metabolites also bond to MAO.
That's interesting. I didn't know that anything was known about the metabolites of Parnate, except that they aren't amphetamine or methamphetamine.