Rivastigmine Monotherapy and Combination Therapy With Memantine in Patients With Moderately Severe Alzheimer's Disease Who Failed to Benefit From Previous Cholinesterase Inhibitor Treatment

This is a prospective, multicenter, open-label study. Following screening and baseline assessments, eligible patients will be switched to rivastigmine and will enter the 16 week run-in rivastigmine treatment phase. After completion of assessments at the end of the run-in phase, patients who were not sufficiently stabilized on rivastigmine alone will receive add-on memantine to their rivastigmine treatment; patients who were stabilized on rivastigmine alone will have completed and be discontinued from the study.