Metronidazole
"I was given 56 pills to take every 6 hours for 14 days (in addition to Clindamycin) for severe tonsillitis.  I'm a third year medical student who will never take for granted prescribing this medicine again.  I'm not sure if it works (this is day 3 and my tonsil is still huge, pus-filled, and incredibly painful) but I feel like I'm experiencing every side effect except the diarrhea.  I'm absolutely hating how I feel right now and just wanted to sound off - to try and release some of this frustration."