The only time I haven't had much success with Azithromycin was when I had a bad case of bronchitis. The Z-pack probably kept it from getting any worse, but it wasn't making it much better.
I ended up having to go on a second round of antibiotics -- Levaquin. That stuff took care of the bronchitis and I felt better pretty soon after starting the medication. The doctor said I just had a really nasty case of bronchitis and one round of antibiotics wasn't going to knock it out. I could tell that much. I was still feeling like crap.