... pins & needles in hands, feet, & face, muscle twitching, dizziness & increased heart rate. Over the last 2 days, my resting heart rate has been 70-80 & as soon as I stand, it goes up from around 120-140. I have to quickly sit. I become dizzy & nauseated. Having tightness in arms & occasionally in chest. Trouble sleeping. I can't walk more than a few steps without sitting. My doctor says if it were Concerta, the symptoms would have been there from the start. Can someone suddenly develop symptoms after using this for 3 yrs with no problems? Should I completely stop taking it or are there risks with that?