Stephen Cox MD, Assistant Clinical Professor of Psychiatry, U.K. College of Medicine.
How does Xanax Work In The Body?
This is a very good question and should be answered before you start taking Xanax. You can't possibly know how best to go off Xanax unless you understand what happens to your body as you are going on it.
Here is what Xanax does in your body. By the way, this is not theory. We actually know this. There is a neurotransmitter in your brain called GABA. It stands for gamma amino butyric acid. GABA is your natural God-given tranquilizer. It is present at 80% of the nerve connections in your brain. When you are too nervous your brain cells release GABA which causes negatively charged chlorine atoms to stream into your nerve cells. That's good because it makes it harder for other stimulating neurotransmitters to trigger the firing of that nerve. If your brain were a car, anxiety might be like the car speeding down a hill toward a sharp curve. As it comes to the curve it must slow down. The car brakes are applied so that the car can negotiate the curve and not burst through the guard rail. The GABA molecules of your brain are like the brakes in your car. If you don't have enough GABA, your brain is going to be like the car speeding toward a curve with worn out brakes! Xanax acts by making what little GABA you do have work more strongly. This is sort of like applying stronger pressure on weak brakes so that your car will negotiate a curve safely.
Decreased benefit develops to the initial dose of Xanax. Xanax does not work as well after two weeks as it does at first. Dose increases by your doctor are necessary in the first weeks of therapy. Why does this happen? For two reasons. One is that your brain cuts back on the release of GABA. It is sort of like your brain says, "Gosh, things are a lot calmer in here now. I don't need to make as much GABA as I used to." Wrong! You didn't have enough GABA to begin with. And now your brain makes even less than it did before you started taking Xanax. Naturally, the Xanax will not work as well as it did initially once GABA is reduced by your brain.
A second reason for decreased benefit of Xanax over time is your liver. It is your liver's duty to get rid of Xanax by making enzymes which destroy Xanax. After you are on Xanax for a while it is as if your liver says, "Hey, we sure are getting a lot of Xanax to destroy these days. Let's make more Xanax-destroying enzymes." And so it does. Let's say your Xanax dose that you started out on was giving you a blood level of, say, 100 units. But after your liver makes more of this destroying enzyme you have a level of, say, 55 units of Xanax. No wonder you feel like the Xanax isn't working as well. It isn't! Even though you're taking the same dose, your blood level dropped. Remember, it does not really make any difference how many milligrams you swallow. What really matters is how much Xanax is running around in your bloodstream.
So, decreased benefit normally develops to Xanax and it is due to either or both of the above reasons. If you didn't understand those two things, go back and read it again because what follows won't make much sense unless you understand those two ideas.