I have long term diabetes w/ poor circulation and was prescribed Levaquin for an infection in the legs. After taking for 2 days I went into tachycardia (fast heartbeat, faint, weak) for almost 7 hours. All the usual tricks for stopping tachycardia would not work until the levaquin had weakened or diluted in my system. I have had this happen within three to six hours after taking now for a total of 6 episodes. Joints hurt but infection seems to be clearing. Legs get positively purple after sitting up more than two hours. Regain normal color after laying down for 1 hour or more...