You may have already reached the end of the possibilties for you with Sinemet, but I hope you haven't given up too soon. My mother initially had a terrible reaction to the Sinemet CR, (gastointestinal problems) and we switched to the generic levodopa/caridopa comination. We had to play with the balance between the L-dopa and C-dopa, but she's taking it now, successfully, with only some tiredness as a side effect.