bacterial infection
"Please make sure you take probiotics or eat yogurt while you're on this.  My abscessed tooth has healed but now suffering from the most horrible chest/heartburn pain I've ever had in my life.  Before I read this post, I was truly thinking I might be having a heart attack.  The pain would go away if I ate something though and I wasn't having pain in my arm or neck.  That's when I Googled and found this site.  I am much relieved that others have had this side effect and It's not just me. (48 yr old female 130 lbs).Was on 300mg x 3 times a day for 10 days."