What Causes Stiffness In Muscles On Using Rasalect For Parkinson S Disease?

Dear sir as i am parkinsonian and has been using syndopa plus 4 tabs every day with 4 hr duration and rasalect 1mg 1 tab every day since 2009.now the drug efficacy has shortend and i was suggested to add another tab before bed .even though my muscle becomes stiffed when i wake up difficult to walk without support. Consulted neuro then one tab Placetran is added twice a day.please suggest isince i fed up with this problem how i cuold be normal to do my works voluntarily even in nights