Unfortunately, I do not know of a medication alternative but have you throught of giving your body a "chemical" break and maybe trying Melatonin for a bit?
My brother was having a lot of sleeping problems and was taking prescription medications for it and eventually he grew a tolerance for it so out of "desperation" he tried Melatonin and it works. It doesn't knock him out or anything like that, but it relaxes his mind enough for him to drift off on his own. If you are interested, you can pick Melatonin up in most health food stores (and many larger grocery stores) and it is really quite cheap.
Sorry - I wish I had a better suggestion for you. I hope you get things figured out.
Teresa