What kind of medications are effective for alzheimer's disease?

A few may help. While there is no cure for alzheimer's disease, there are a few prescription medications that slow its progression. (the amount they help may or may not be clinically significant, though — researchers disagree on this point.) examples include Aricept (donepezil), Namenda (memantine), and Exelon (rivastigmine).
Four. Three of them are inhibitors of acetylcholine breakdown (aricept, Exelon (rivastigmine) and razadyne) and one is affecting glutamate receptors (namenda).