I just wrote a quick review of a study just published this week regarding memantine (Namenda) which concluded that it offered no benefit in mild Alzheimer's disease.
Typical side effects include dizziness, confusion, headache, constipation, hypertension, cough, pain, hallucinations, somnolence, vomiting, dyspnea and/or fatigue as per www.epocrates.com.
Donepezil (Aricept) is in the family of acetylcholinesterase inhibitors (along w/galantamine, rivastigmine & tacrine). Typical side effects for all include nausea, headache, diarrhea, pain, insomnia, dizziness, muscle cramps, fatigue, vomiting, anorexia, weight loss, depression, dream disturbance, syncope, arthritis, somnolence, and/or urinary frequency as per www.epocrates.com.
Might I inquire (or suggest that you look) into legal & practical measures? For instance, have you decided upon estate planning while you still have a say in the matter? You'd hate to have your family members arguing after your passing. Speaking of which, do you have a living will and/or durable healthcare power of attorney? Who have you designated to speak on your behalf? Again, you'd hate to have your family members fighting over what they think you wanted. Have you talked to them about respite, hospice & palliative care?
What about practical matters such as when to give up driving? At which point, how are you going to get around? And while you have a choice, do you live close enough to one of your children who's agreeable to helping you? Or do you foresee having to move closer to one of them at some point in time? Or perhaps move into a continuing care retirement community?
What I'm trying to get at is this: it's time for a family meeting where you tell everyone what you want while you can still do so. Best to let them know what you want and to have someone (family attorney?) document it. Then go out and enjoy yourself!
Best wishes on this final journey. By the way, there are some who feel that you may be able to delay the inevitable by aggressively managing vascular risk factors, eg blood pressure, cholesterol & sugars. But you have to take care of all of them, not just some. You might also consider enrolling in clinical trials with a nearby dementia research center. If you're feeling alone, check out the Alzheimer's Association, among others, for information. I've also posted a number of times on the topic on my blog. Again, best wishes and God speed.