For people with Alzheimer's or mixed dementia how effective are cholinesterase inhibitors augmented with memantine compared to cholinesterase inhibitors (ChEI) alone / placebo in achieving improved outcomes in terms of cognition, function, delay to institution, and carer burden / stress?
systematic reviews, of moderate to high quality, provided evidence
to inform this summary. The reviews were only able to identify a
small number of RCTs (a total of four different studies, with two
RCTs being common to both reviews). Both reviews reported some
evidence of a small benefit from adding memantine to donepezil in
patients with moderate to severe Alzheimer's disease; outcomes
assessed included clinical global score, cognition, function, and
behaviour and mood. When patients with mild Alzheimer's disease
were included in the analyses (one review), only function was
significantly improved by the addition of memantine. The authors of
both reviews concluded that it is currently unclear clinically
significant outcomes can be achieved using combination therapy.
These conclusions are a reasonable interpretation of the available
evidence and are likely to be reliable.
Further studies are needed to confirm the findings of the two
systematic reviews included in this assessment. More data are
particularly needed for patients with mild Alzheimer's disease and
for patients with other dementias; no studies which included
participants with any other dementia types were identified. Studies
assessing combination therapy using memantine and ChEIs other than
donepezil may also be useful.