This is a prospective, 26-week, open-label, single-arm multi-center pilot study. Eligible patients will receive open-label treatment with rivastigmine capsules plus memantine tablets as add on therapy. This study is designed to evaluate the safety and tolerability of add on therapy with memantine to rivastigmine capsules in patients with probable AD (MMSE 10-20)

Inclusion Criteria:

• Have a diagnosis of probable Alzheimer's disease;
• Have an MMSE score between 10 and 20;
• Must be able to swallow capsule/tablet;
• Must have a caregiver who is able to attend all study visits;

Exclusion Criteria:

• Have an advanced, severe, progressive, or unstable disease of any type that may interfere with efficacy and safety assessments or put the patient at special risk;
• Have a current diagnosis of active, uncontrolled seizure disorder;
• Have a history within the past year or current diagnosis of cerebrovascular disease
• Have a current diagnosis of severe or unstable cardiovascular disease;
• Had a myocardial infarction (MI) within the last six months;
• Have specific respiratory, digestive, renal, or endocrine disorders;
• Have had previous treatment with rivastigmine or memantine;

Other protocol-defined inclusion/exclusion criteria may apply