Well, break it to your doctors gently but the mechanism of Amantadine on pd remains unknown and it is listed separately from anticholinergic drugs.
http://www.scribd.com/doc/24033066/A...ticholinergics
http://www.ncbi.nlm.nih.gov/bookshel...ons&part=A3600
not much has changed in the time span between these two publications.
paula