Current treatment of Alzheimer's disease (AD) has focused on the use of cholinesterase inhibitors. This review emphasizes emerging therapies for the treatment and/or prevention of AD with a focus on glutamatergic excitotoxicity in dementia and the therapeutic promise of the uncompetitive, low to moderate affinity N-methyl-D-aspartate (NMDA) receptor antagonist, memantine. Preclinical studies and clinical trials in AD, as well as the extensive clinical use of memantine for neurodegenerative conditions in Europe since 1982 support the safety, tolerability, and efficacy of this agent. Memantine was recently approved in Europe for the treatment of moderately severe to severe AD and is an investigational drug in the United States.