Joan - I am also a pwp who needs Amantadine in addition to Sinemet for sustained efficacy of my symptoms. I had only been taking Sinemet for three years when the drug stopped being of much help. Amantadine was added and made all the difference in the world in alleviating the symptoms. During the nine years since then, there have been numerous occasions when I missed taking Amantadine for from 1 to 2 days and would go into almost a frozen state. Then after taking Amantadine once again I would be functioning even better than I was just prior to missing the Amantadine dosages and would remain better for several weeks. My neurologists have appeared quite surprised at how long I have taken Amantadine and how well it works for me. I have no side-effects that I'm aware of but I did have the purple mottling of the skin around my ankles when I first started the drug but that has been gone for many years. It seems to me that my parkinson symptoms have stayed at the same level or degree for nearly ten years...since I started taking Amantadine. I am certainly grateful for this drug! Janice Long ...(Jan) 54/20