Cefdinir
"I was prescribed Cefdinir after getting a sinus infection and bronchitis.  It solved that problem in just a few days, but after 3 days on it, my diarrhea became intolerable, far worse than the original sickness.  I stopped taking Cefdinir.  It's been over 3 weeks now of non-stop gastrointestinal pain that landed me an clonoscopy procedure, stool cultures at the hospital, and persistent diarrhea.  The worst of which culminated in a near black out from pain on the toilet.  My case may have been a rare exception but I'm certain Cefdinir is no friend of mine."