Motegrity and side effects in advanced Parkins;n's disease

Iwo am dealing with a person with advanced(20 year +) parkinson's disease. Recently motegrity was added for constipation. Since disease symptoms vary from day to day, it is difficult to be sure, but there may be increased tremors. Since the patient has increased tremors with SSRI's , two questions: has any one with this situation noted increased tremors in advanced PD and motegrity? and 2 Does motegrity cross the blood brain barrier?