Posted by christophrejmc on March 31, 2002, at 1:02:03
In reply to FACHAD: follow-up question #2 re MAOI's! » fachad, posted by Janelle on March 30, 2002, at 15:31:18
(Hope you don't mind me answering your question directed to fachad...)
> why, if MAOI's are designed to inhibit MAO, are there a bunch of different brands of them - is the chemical structure of each MAOI different so each MAOI acts on several different things (besides MAO) and these things vary from MAOI to MAOI ... like the way I was told that each SSRI affects several different things, and these things vary from SSRI to SSRI (they all do not just affect Serotonin), and this is why different people react differently to the various SSRI's. Is it like this for MAOI's also?
There are two major differences in the MAOIs: selectivity and reversability.
There are two subtypes of MAO, A and B; some MAOIs selectively inhibit only one isozyme, the others inhibit both (although not always equally).
Reversability pertains to how an MAOI binds to MAO. Once an irreversable MAOI binds to MAO, it cannot be detached. The reversable inhibitors (all of which selectively deanimate MAO-A (the subtype responsible for most of the destruction of tyramine)) only bind to MAO for a short while and can be displaced by certain biogenic amines (most importantly tyramine), thus there is a very low risk of tyramine-induced hypertensive crisis.
There are also differences within each group unrelated to MAO inhibition (like the SSRIs).
Also, in reference to your first question: I don't think your initial BP would really matter. (MAOIs actually decrease BP for most people, by the way.) Your BP might not increase as much as someone normo-/hypertensive, but I believe it would still be at an uncomfortable level. If you think that you have Neurally Mediated Hypotension, there are medications used to treat it...
Hope this is of some help.
-Christophre
poster:christophrejmc
thread:100948
URL: http://www.dr-bob.org/babble/20020327/msgs/101055.html