I assume that the medication is '
clonazepam', although it doesn't matter too much as all of those meds are essentially the same, except for the half-lives and onset times. You are partially
correctCorrect (new formula); the rebound anxiety from Xanax often results in worse symptoms than the original anxiety disorder-- which is why many doctors hate to prescribe that class of medication. Like pain pills, they are subject to tolerance-- and all of the problems that come with tolerance, like urges to take more and more, and loss of efficacy of the medication. Clonazepam has the longer action, and so there is not the 'uncovered' times when anxiety roars back-- but because it is always there, tolerance develops even more quickly to its actions. There is 'cross-tolerance' between the meds in this class, so if Xanax doesn't work, clonazepam won't work either-- unless given at a higher dose.
Those medications work at the exact same receptor site as alcohol, and are used to treat alcohol withdrawal. Withdrawal from both alcohol and benzodiazepines can cause seizures and can even be fatal; clonazepam withdrawal is a bit safer, as the long half-life allows it to taper itself. The main difference for you will be that Xanax comes on fast-- in 15 minutes-- whereas clonazepam takes over an hour to get absorbed, so the onset is much more subtle.
In general these are lousy treatments for long-term anxiety; the treatment of choice is a serotonin drug like prozac or citalopram, or an 'SNRI' like effexor. The benzos are great for a couple weeks.... but for the long term they usually end up as a ball and chain.