If you look in the Resources thread here I think they give a benzodiazepines equivalency chart. Which would give you an idea of which medications would be around the same strength as what you're taking now. Unfortunately, benzos build tolerance very quickly, and the only way to keep getting the ability to sleep is to not use them regularly. For sleep they're only good for about 2 weeks. I think they maintain their effectiveness for anxiety though. Can you speak with your doctor about adding something else to help you sleep? 4 mg of Xanax is a pretty high dose. You may want to Google the Ashton manual, which is the gold standard for reducing or completely getting off Benzos. Dr. Ashton studied their effects a lot. But she's not some anti-drug zealot, in fact her first stipulation is that no one should be forced to go off their meds, it should be their decision. It's worth a glance if you've been on that high a dose for a year. And a disclaimer from me, I'm not saying whether you should either.