Posted by bassman on October 19, 2006, at 17:55:16
In reply to Re: Generic alprazolam vs. Xanax name brand, posted by valene on October 19, 2006, at 13:02:12
Somewhere I have a reference to a journal article in which subjects taking Xanax were switched to generic and they all showed signs of withdrawal.
The 20% thing isn't as bad as you might think-it isn't that the tabs themselves have to be within 20%, they have to be within about 5% over all. It is the bioavailability that is +/- 20%. That seems like a lot, but what is measured is the blood concnetration of the drug-and that is all over the place for different people and also because the technique usually used to measure blood levels, mass spectrometry, isn't particularly precise or accurate. Check out the data on a package insert some time on blood concentrations of drugs and see the huge range for subjects.
So it's reasonable to have the 20% for bioavailability, but the problem is that you never know if it because of the inherent inaccuracy of the method used or because the generic isn't as bioavailable. As you wrote, with alprazolam, that's critical.
Generics just cost the pharmacist pennies per tab, so they really should at least use a decent generic house. Alprazolam is sold some places for about 12 cents a tab, and that's with an excellent profit.
poster:bassman
thread:696040
URL: http://www.dr-bob.org/babble/20061011/msgs/696124.html