Metronidazole
"My GYN prescribed me 500MG every 12 hours for 7 days. When I picked it up, the pharmacist warned me that it could cause nausea. The first two days I felt kind of sick, I had pretty severe upper abdominal pain and it lasted for hours, I felt like if I ate I would throw up. The third day I threw up twice and noticed that my urine was very dark, despite me staying very hydrated. Tonight I will take my last dose and I could not be happier. I have thrown up six times in the past week and spent hours in agonizing pain laying on my side hoping it would go away, it only ever felt better when I threw up. I definitely don't recommend staying on this medication for a long period of time, but it has effectively taken care of the bacterial infection."