What Causes Depression While On NamendaXR For Dementia Disorder?

My mother is 87 with Dementia and recently had a ministroke. She was put on NemendaXR and became totally different person. Sad, depressed able to escape at night (which she fears the dark) and doesn t reconize her home at all. All changes have been made to prevent that from happening again but it hurts to see her so depressed and crying wanting to go home all the time. Her memory is back to her teenage years alot worse than before she was put on it. My dad had 2 mini strokes before he had his fatal one but he never was like this. Off course he did not have the dementia either. She is on her 3rd week and I see nothing but down hill. She is 87.