I started taking this medication on a Tuesday... by Friday I started to notice a ringing in my ears.. I also had dark colored urine..and a metallic taste in my mouth. I stopped taking the medication because I couldn't stand the ringing in my ears.... it has been almost 1 week since I stopped.... my urine color is normal.. but the ringing in my ears is still there and I now have diarrhea. I can't handle the ringing anymore.... how long should side effects last once the meds are done????????? Also, after reading some of the other notes, I too had a pain/soreness in my back.