Hello,
Aricept is the initial choice in mild Alzheimers and as it it progressions Namenda is started to improve cognition in moderate and late Alzheimers. However, both can be used to improve the well being.
If your mother is allergic to Aricept, you may well go for Namenda, but be aware of the adverse effects like
dizziness, headache and confusion. Did Aricept have similar side effects, which troubled her? Also, being 97, renal condition should be good to start Namenda.
If is unable to identify reality and is hallucinating, you can try anti-psychotic medications like ariprazole or
haloperidol ( Still not FDA approved for Alzheimers).
Get a prescription from your doctor for Namenda as it will improve the well being in later stages.
Whenever you start a new drug, ask your caregiver to watchout for side effects. and dosage should be started slowly and increased depending on patient response.
Hope I have answered your query. If you have any further queries, happy to help.