as far as i know it doesn't effect glucose levels.
the cause for needing it can effect glucose levels though, i.e. the infection, so if BG level goes back up some, i wouldn't be in a super rush to go back on insulin until maybe after the infection clears up some
i also think it may cause some tummy upset, which can effect appetite, so keep an eye out for that. i'm drawing a slight blank though on which antibiotic it is that causes that for sure so hopefully someone else can make certain of that for both of us