Amoxicillin / clavulanate
"I took this medicine for a tooth abscess that couldn't be drained during root canal. Severe diarrhea, headaches, minor heartburn and I felt as though my throat were closing (doc said minor allergic reaction). I have been taking a probiotic and eating yogurt but it hasn't helped with the stomach upset at all.  It helped with the abscess but 8 days later it isn't completely cleared. I've been switched to Clindamycin due to the tightening in my throat. Scared to death and sick of antibiotics."