Progress in clinical neurosciences: Treatment of Alzheimer's disease and other dementias - Review and comparison of the cholinesterase inhibitors

Background. Alzheimer's disease (AD) is the most common cause of dementia in older adults. Acceptance of the cholinergic hypothesis led to a search for medications which could enhance central cholinergic activity in this condition. There are now three cholinesterase inhibitors available for the treatment of AD in Canada. Objectives: To review the currently available cholinesterase inhibitors approved for the treatment of AD in Canada and to provide guidance on who and how to treat with these agents. Results: Donepezil, rivastigmine, and galantamine are approved for the treatment of AD in Canada. In clinical trails, patients with mild to moderate AD treated with these agents experienced modest improvements in cognition, function, behaviour, and/or global clinical state. The magnitude of benefits seen with each agent appeared to be similar. While to date, there is no convincing evidence that one is more efficacious or effective, they do differ in their pharmacokinetics, additional mechanisms of action, and side effect profiles. Therefore, the selection of agent will be based on considerations such as side effect profiles, ease of administration, personal familiarity/experience, and beliefs about the importance of the noted differences in their pharmacokinetics and additional mechanisms of action. Conclusion: We believe that these agents should be offered to all individuals with a mild to moderate dementia where Alzheimer's pathology is felt to be a contributing factor. We view all three available cholinesterase inhibitors as first-line drugs.