Donepezil, rivastigmine, galantamine and memantine for ...

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Clinical effectiveness
This appeared generally to be related to higher
doses of rivastigmine, but, it was not tested for
statistical significance in the two published trials.
[Commercial/academic confidential information
removed] Two trials showed no difference in the
rates of withdrawals and one 57 demonstrated a
higher proportion in the placebo group, but these
were not tested for statistical significance. Very few
deaths were reported. All data relating to
withdrawals and deaths can be found for the
individual studies in Appendix 8.
Summary
● Four published RCTs on the effectiveness of
rivastigmine met the inclusion criteria for this
review. All four trials were sponsored by the
manufacturer. The quality of reporting was
generally poor for two of these. None of the
trials lasted longer than 26 weeks. Only two of
the trials reported an adequate method of
randomisation, and only one of these clearly
reported concealment of allocation. The other
three may therefore have been subject to
selection bias, which would affect interpretation
of the results. Withdrawals were not adequately
described by two of the trials, and attrition bias
may therefore affect the results of these. None
of the trials reported assessor blinding
adequately, so measurement bias may need to
be taken into consideration when discussing the
trials’ findings.
● Two unpublished studies were included in the
review. [Commercial/academic confidential
information removed]
● Statistically significant differences between the
6–12 mg/day treatment groups (mean dose
~10 mg/day) and placebo were reported by two
of three published trials which reported ADAScog
and MMSE. No statistically significant
effects were seen in the low-dose treatment
groups in these studies. Forette and colleagues 60
found that participants receiving twice daily
doses of rivastigmine scored statistically
significantly better on the Wechsler logical
memory test than did those receiving the drug
three times daily. However, sample sizes were
very low (