Patients with dementia associated with Parkinson’ s disease experience some side effects more frequently and also some additional side effects: trembling (very common), difficulty in sleeping, anxiety, restlessness, worsening of Parkinson’ s disease or development of similar symptoms (muscle stiffness, difficulty in carrying out movements), abnormally slow or uncontrollable movements, slow heart beat, too much saliva and dehydration (common), irregular heart beat and poor control of movements (uncommon).