I'm on Biaxin for a respiratory infection as well, the worst side effect by far is the severe insomnia, and crazy dreams I get when I finally DO fall asleep - and the sleep I get isn't restful at all. I also have turned into a "bed tosser" - I toss and turn all night because I can't sleep comfortably in one position all night (I usually fall asleep and wake up in the same position, and maybe turn once a night.) Its like all of a sudden I get sore being in any one position for more than an hour. Drives me nuts.