Figure 7.

The drugs approved by the US Food and Drug Administration for treatment of Alzheimer’s disease at different clinical stages.

Aricept^®, Exelon^®, and Razadyne^® are acetylcholinesterase inhibitors that block breakdown of the neurotransmitter acetylcholine by the enzyme acetylcholinesterase and thus they increase level and action of the neurotransmitter in the brain of Alzheimer’s disease patients. Namenda ^® is a glutamate receptor antagonist that blocks the damaging effects of excessive amount of glutamate, also a neurotransmitter, produced in the brain of Alzheimer’s disease patients.