spencersok — it looks like my first post did not address your question. I didn't have any significant side effects from the Levaquin. It helped the first couple of times but this last time, it didn't. Further testing and a cat scan of sinus showed a deep infection that they think is causing the cough at this time. I was told at the ER that it is possibly too deep for antibiotics to reach and I'm set up with an ENT in two weeks to see if they can get it out. But….. I think you'll be okay with 500 mg Levaquin. I tried the 750 once and didn't get along well with it.