Drug therapies for Alzheimer's disease

Abstract

Dementia is a progressive, irreversible decline in cognition that has impacted on the patient's pre-existing level of functioning. Alzheimer's disease (AD) is the most common cause of dementia. Therapeutic efforts thus far have concentrated on prevention, disease modification and symptom management. Currently only drugs for symptom control are available. The acetylcholinesterase inhibitors (AChEs) donepezil, galantamine and rivastigmine and the N-methyl-d-aspartate (NMDA) receptor antagonist memantine are licensed for the management of AD. Consistent evidence from clinical trials in AD shows modest clinical benefit from AChEIs, and, in more severe disease, from memantine therapy. All four drugs are available in oral preparations, rivastigmine is also available as a daily transdermal patch. Contraindications to and adverse effects of AChEI treatment are in keeping with the physiological effects of acetylcholine. Non-cognitive symptoms can be markers of comorbid pathology or symptomatic of worsening AD. AChEIs and memantine have been shown to be of discernible clinical benefit in these cases. Antipsychotic drugs reduce agitation, aggression and psychosis but also confer a higher risk of serious adverse effects. Drug therapies are a single facet of the comprehensive assessment and treatment of patients with AD.