Contemporary issues in the treatment of Alzheimer's disease: tangible benefits of current therapies.

Because of the mild symptomatology associated with its earlier stages, Alzheimer's disease (AD) is most commonly diagnosed in an intermediate to late stage of progression. Patients with moderate to severe AD at diagnosis have already experienced appreciable losses in cognition and functioning. However, such patients may still benefit greatly from the use of antidementia agents such as cholines-terase inhibitors (ChEIs) and the N-methyl-D-aspartate (NMDA) receptor open-channel antagonist memantine. Monotherapy regimens involving a ChEI or memantine have been shown to slow the progression of cognitive symptoms in patients with moderate to severe AD, although memantine is currently the only agent approved for use in this setting. Furthermore, combination therapy involving memantine and a ChEI has been shown to yield increased cognitive benefits relative to ChEI monotherapy, a result that is believed to be attributable to the distinct therapeutic mechanisms associated with NMDA receptor open-channel antagonists and ChEIs. Nonetheless, recent findings indicate that the therapeutic effects of these antidementia agents are not limited to cognition. For example, emerging data highlight the efficacy of ChEIs and memantine, used either alone or in combination, in improving outcomes related to patient functioning and behavior, 2 domains that may have a great deal of significance for patients and caregivers. Furthermore, recent clinical trial data suggest that antidementia agents may significantly delay nursing home placement, a unique endpoint that can be tremendously distressing to patients with AD and their caregivers. Thus, it is clear that the ChEIs and memantine provide substantial benefits that extend across the spectrum of symptoms of AD, improving outcomes for those who are affected, either directly or indirectly, by this debilitating condition.