Azithromycin
"I've used this medication in the past and now recently for a bad throat infection, I was given the 5 day pack, after the first day (2 tablets) taken it started to feel better... And slowly it's been improving everyday. I did experience bad stomach side effects, diarrhea mainly, but I expected that since I wasn't eating well from the throat infection.  Took my last tablet today and I hope that it's gone but the symptoms have definitely improved. If you do get an upset stomach try to take it with food.  Good medication all in all though."