Azithromycin
"I have Still's Disease and chronic Sinus infections.  Zithromax the brand will clear the sinus up for a couple of weeks to a few months.  Twice now I have used Azithromycin generic for 5 days, instead of the brand, when all of the local pharmacies were out of brand.   Both times it has done nothing.  I don't know if this is because my immune system is a little sensitive due to the Still's. Just know the brand works for me and Azithromycin has no effect. I just get sicker and with my Still's that can be terrible."