Anyone had luck with medication to take the edge off sundowning/ restlessness in very mobile person with Alzheimer's?

My mother who has younger onset alzheimers is always on the go. In some ways it is good because she is positive and motivated and keen to get out and be social , but during the sundowning period from aout 4pm she STILL wants to " get going" and won't wind down or relax.
She walks in and out of rooms in the house telling me to hurry up because everyone is waiting and we need to get going. She loves being in the car, so sometimes when this is happening I will take her to the supermarket but as soon as we are out of the car she starts saying " come on we need to get home".
So it is almost like she is NEVER satisfied with where she is and needs to keep going somewhere.
She also pulls all the sheets off her bed during this time too. if I remake the bed she just pulls it all apart 10 minutes later.
It is very tiring. It only stops once she has had a bath and in bed.
She isn't being aggressive or hallucinating..it is just annoying and I wish there was a way to take the anxious 'edge' off so she could relax.
She does sleep well through the night thank fully.
She has been on zoloft for many years and The doctor has now also prescribed Risperdal for the sundowning, which I haven't tried yet as.
I have read some bad reviews and I'm very cautious to give her anything that may trigger more of a progression of the dementia.
Has anyone had any experience with this drug?
Anyone else have a similar restless alzheimers loved one on another drug that has helped?
Thanks in advance.