Xanax (the generic name is alprazolam) is one of the commonly prescribed antianxiety medicines in the class called benzodiazepines. Other drugs in this class are clonazepam (Klonopin), diazepam (Valium), lorazepam (Ativan) and chlordiazepoxide (Librium).

I'm not sure I would use the word "severe" when comparing the risk of withdrawal from Xanax to the risk for many other drugs in this class. The withdrawal from any of these drugs can be severe, moderate, or mild depending on many factors. I'm reluctant to single this drug out for special status.

Generally speaking, the intensity of withdrawal symptoms and the risk of getting them goes up the longer you've been taking the medication, the higher the dose has been, and the more rapidly you stop it. If you've been taking any benzodiazepine at a relatively high dose for a long period of time (months to years) and you suddenly stop, you will be at greater than average risk for getting withdrawal symptoms.

Xanax might be viewed as a risky choice because it is relatively potent. For example, 1mg of Xanax is equivalent to 10mg of Valium (generic name, diazepam). Doctors adjust for potency when prescribing a dose. However, since 1mg sounds like less than 10mg, there may be a tendency for Xanax doses to creep higher.

More importantly, Xanax leaves the body more quickly than some other benzodiazepines. Doctors call this a "shorter-acting" drug. Let's compare it to Valium again: after one dose of Xanax, the blood level decreases rapidly over several hours, while Valium sticks around for days. If you stop taking Valium suddenly, the blood level would decrease more slowly and you would withdraw more gradually than if you had suddenly stopped taking Xanax.

Some people worry that shorter-acting benzodiazepines cause dependency (and withdrawal) more quickly than longer-acting ones. But the more common problem with shorter-acting benzodiazepines is not withdrawal, but rebound. If you use Xanax to treat anxiety, the quicker the drug leaves your system, the quicker the anxiety symptoms will come back.

In practical terms, all these drugs are very effective to treat anxiety and relatively safe, too, especially if you maintain a stable dose. In the real world, people often forget to take their medication from time to time. Anyone taking shorter-acting benzodiazepines is more likely to notice a missed dose than someone taking a longer-acting one.

Because the drugs in this class are so similar in their basic actions, there is a solution for people who are ready to stop taking Xanax. A person who develops withdrawal symptoms while trying to stop Xanax can switch to an equivalent dose of a drug like Valium or Librium, then taper the dose very gradually.