Effectiveness of Adding Memantine to an Alzheimer Dementia Treatment Regimen Which Already Includes Stable Donepezil Therapy

Abstract

Alzheimer dementia (AD) is a major cause of debility and economic strain in aging societies around the world. The only 2 medication classes approved specifically for the treatment of AD are the cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and memantine. Evidence that the use of memantine in a patient already on cholinesterase inhibitor therapy can provide a clinically significant benefit is limited. To review the evidence supporting the addition of memantine therapy in patients with moderate-to-severe AD who are already receiving treatment with a cholinesterase inhibitor. The objective was addressed through the development of a critically appraised topic which included a clinical scenario, structured question, search strategy, critical appraisal, results, evidence summary, commentary, and bottom line conclusions. Included were neurology consultants and residents, a medical librarian, clinical epidemiologists, and content experts in the field of behavioral neurology. One article was selected for review. Patients receiving memantine for 24 weeks experienced a statistically significant change from baseline on a modified 19-item AD Cooperative Study-Activities of Daily Living Inventory (P=0.03) and on the Severe Impairment Battery (P=0.001) when compared with placebo. The change in mean scores in the memantine group versus placebo on the 19-item AD Cooperative Study-Activities of Daily Living Inventory were -2.0 versus -3.4 and on the Severe Impairment Battery 0.9 versus -2.5 which indicate improved performance or reduced deterioration in the memantine group. The number needed to treat and the effect size could not be calculated from the data provided. The addition of memantine to donepezil in patients with moderate-to-severe AD provides a statistically significant improvement in several AD-oriented outcome measures, however, the clinical relevance of this benefit remains unclear.