My husband had nightmares when he started taking Aricept.
He had to stop taking it.
I have had vertigo a few times and was told it was post viral, although I was never aware of any symptoms of viral infections. Another cause of vertigo is middle ear fluid. It is a very unpleasant experience and, in severe cases, can result in vomiting.
There is a difference between vertigo and dizziness.
My husband often complains of dizziness, especially in the early evening. I associate it with his `lapses`.
The only person who can really identify the cause is the GP.