Current and Investigational Drugs for Treatment of Alzheimer's Disease

Alzheimer’s disease is characterized pathologically by the presence of neuritic plaques containing β-amyloid and neurofibrillary tangles containing tau. These have become two targets of investigational drugs aimed at preventing or slowing the disease. Early findings of extensive cholinergic degeneration inspired the development of drugs targeting cholinergic function. Cholinesterase inhibitors were the first drugs to be approved for treatment, followed by the NMDA receptor antagonist memantine. This chapter will focus on the development, mechanism of action, and results of clinical trials for drugs currently used or in development for treatment of Alzheimer’s disease. Examples of these include drugs targeting cholinergic neurons, such as cholinesterase inhibitors, muscarinic receptor agonists and nicotinic receptor agonists, as well as memantine. Several drugs aimed at reducing levels of β-amyloid or tau are in development and will be addressed. Finally, drugs directed at other targets that may be useful in treatment of Alzheimer’s disease will be discussed.