I've been having this sort of burning, gassy feeling in my abdomen for about a month or two. It was never really painful or that noticeable until a week ago. I was in excruciating pain last Friday after eating spaghetti and drinking a beer. Seems like the bacteria caused an ulcer. Well, I was prescribed a Prevpac and that is the worst thing ever. I've taken two doses and now I'm certain I can never take another one. The doctor initially prescribed Zantac 150 until the tests came back positive and that actually had me pain free for a few days. There is this constant pain in my abdomen since starting the Prevpac and I haven't taken a dose since 7 a.m. this morning. Has anyone had any similar experiences with Prevacid, Biaxin or Amoxicillin?