How long does it take after starting antibiotics for bladder infection to clear up?

24-48hr for symptoms. You should start noticing a difference in the first 1-2 days after starting the antibiotics. However, even though the symptoms improve, you need to finish all of your antibiotics - this kills any remaining bacteria you have and prevents creating resistant bugs. I tell patients if they're not feeling at least a little better after 2 days worth of abx, to let our office now.