Is there a treatment for the obvious "sundowners" syndrome?

Excellent article on this very website.

https://www.agingcare.com/articles/sundowners-syndrome-133187.htm

I've found pretty much the same thing that keeping the person active and devoting all your attention on her during that time
Often if I'm on the phone or try to do stuff on the computer, she'll become very agitated. It's almost like a sense of insecurity or fear that is felt during that time and it's difficult to verbalize it.
Have you tried some medication like Buspar? That often helps, my mom will sleep for 30 mins and wake up like a different person

Jeannegibbs, She does have problems with taking her meds. She has a dispenser that beeps and a light flashes. Problem is she will forget she took morning meds, (or something), and force the dispenser to turn. So she may be taking meds some days at wrong time. When I opened the box night before last to add pills she ran out of, there were two empty spaces. I adjusted it to the right dose, gave her night meds and scolded her for "messing with her meds". She will say "YOU must have skipped a couple days". There were 5 more days left, so no! I didn't leave spaces empty. She is in a retirement home where they do most things, but don't do meds. I thought the dispenser would solve that, but she learned she could turn it by hand if she thinks it's time for them and none in the box. I may have to find a box that actually cannot be turned manually. Anyone know of any?

There's nothing that will cure sundowner's. It may help to stick to a routine and if you see signs of impending agitation gently redirect her attention to something else.

We tried to avoid late afternoon outings which would cause us to return after dark. We also tried activities that began in late afternoon and continued into the evening.

The best treatment seemed to be to keep the person occupied with very familiar activities to transition into the evening, and stay with her until bedtime.

As far as I know, there is no specific treatment for the sundowners aspect of dementia.

Is she usually OK taking the medicines on her own?