My mother is new to Memory Care in an assisted living facility. The in-house medical group recommends discontinuing her Namenda due to "scientific evidence" that it is no longer useful or effective after 5 years of use. Her Geriatric Specialist indicates it can be discontinued for 1 month and if there is a decline, my mom can go back on it. She is in the Severe Stage. What do we do? She walks, talks, laughs and is full of joy. She loves music and participating in small group activities. She requires support with all activities of daily living and hygiene.
If I were in your shoes I'd go with her geriatrician's advice. Discontinue, observe, and re-introduce it if it seems to make a difference. Have the doctor put that in writing, in hopes of reducing a hassle if you do decide to put her back on it.