Where do all the drugs go?

Ever wonder why meds get yanked from the market after supposedly being ruled safe by the FDA? I did. I remember using Bextra, with wonderful results, for really bad menstrual cramps for a few years…and then BAM! It was pulled from the market. Personally I was thinking “WTF?” I had used the medication for 4 years with no problems…no nausea or anything. So what could’ve possibly happened to make my miracle drug disappear like that? I know I’m not the only person this happened to. So what exactly happened? And why should anyone care?