Would 5 mg of Namenda make you very sleepy?

The doctor put my Mother on Namenda. She was diagnosed with moderate dementia. He wants her to take 2 -5mg pills a day. One in the morning and one at night. She has only been taking the one in the morning because she has been forgetting the nighttime dose. But she seems to be sleeping alot more. I think one of the side effects of this medications is sleepy. But could only 5 mg cause her to become sleepy?

He also put her on a pill that he said is for the kidney and also does blood pressure. Not sure of the name but her blood pressure is normal. He said she could use it for the kidneys. I wonder if that could be making her sleepy.

Any help with this subject would be greatly appreciated.

Also has anyone had good results with Namenda and on how much of a dosage.