I now remember the guy's name. IlAdvocate. I believe it was for scizophrenia, and they used glycine as the glutamate antagonist. Go to the home page and contact this person for some good info on glutamate.
There is someone on this forum, or the depression forum, who was in a clinical trial with a medication targeting glutamate receptors for bipolar disease and claims to have been cured by it. You can find her posts in the archives, and she should be a good source for you. However, glutamate is considered largely for depression because it is stimulating to the brain, not calming. On the other hand, if you reduce glutamate and, presumably, one of its precursors, glutamine, you run the risk of muscle wasting. It is also involved with GABA production. I'd research this one pretty thoroughly before I'd treat an anxiety disease by possibly increasing weakness and depression, since depression and anxiety often go together. NAC shouldn't hurt you in this area, and it's a great antioxidant, but I don't know about the medications mentioned.
For the best possible advice about these medications, please go to our OCD Forum. The good and kind folks there will know far more about these drugs then we do on the Anxiety Forum.
Just go back to the Forum directory and scroll down to OCD.
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Greenlydia