Get her doctor to change the prescription to a liquid form of the drug. And then put it in her food. I had to do this with my 89 year old father after he tried to kill me one morning. (He was getting ready to hit me over the head with his huge metal flashlight--I heard him just in time and was able to swing around and confront him. He tried to pass it off as my "overreacting" but I immediately went to his doctor and got him the drugs!)
You have to make sure she is going to eat all of it, so choose something to put it in that is her favourite. And measure the drug very carefully--it can have nasty side effects if you get the dosage wrong.
My Dad was a PLEASURE to be with the last 4 years of his life, because of this drug. The anger and psychosis just disappeared.