Like AnnT, I too have had similar response to Amantadine.
Each of my Trial evaluations as been off meds for 12-hours. When I take my first meds that day...mid to late morning...I take 100mg Amatadine, 1-1/2 C/L 25/100 and .5mg Mirapex and see a maked change in my tremor.
Tremor was driving me into DBS until CERE-120 Phase II came available.