Memantine's effects are small but "clinically noticeable" after patients take 20 milligrams of the drug daily for 28 weeks, according to Dr. Rupert McShane of the University of Oxford and colleagues. The effect of memantine was measured by a variety of tests that rate a patient's thinking skills, daily activity and mood.
While there is no evidence that the drug can treat agitation in Alzheimer's patients, it does appear to prevent the onset of agitation, the review finds.
The studies also hint at some cognitive benefits from the drug for patients with mild to moderate Alzheimer's and vascular dementia, which occurs when brain cells are starved of oxygen by blocked or diseased blood vessels. However, these changes were not clinically significant, and it remains unknown whether there is a true benefit in mild to moderate cases, McShane and colleagues write.
The Food and Drug Administration approved memantine for the treatment of moderate to severe Alzheimer's dementia in 2003. The European Agency for the Evaluation of Medical Products approved the drug for similar indications in 2002. Manufacturers of the drug in Europe and the United States have applied for approval of the drug for mild to moderate Alzheimer's dementia.
The review appears in the April issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The review included nine published studies comprising 2,339 participants, but three important trials have not yet been published.