Current AD medications, which can help with memory symptoms and other cognitive changes, can be grouped into two drug categories:
- Cholinesterase inhibitors: These medications work by preserving chemicals in the brain that are important for cell to cell communications. They also improve neuropsychiatric symptoms including agitation and depression. However, at best the improvements are modest. Moreover, there are many side effects caused by these drugs including loss of appetite and sleep disturbances as well as more serious side effects such as cardiac arrhythmias.
- Cholinesterase inhibitors work by inhibiting the breakdown of the neurotransmitter acetylcholin in the brain. They are prescribed mainly to treat symptoms of mild to moderate AD. Two main cholinesterase inhibitor drugs approved by the FDA are Aricept® (donepezil) and Exelon® (rivastigmine).
- NMDA antagonists: These drugs are N-methyl D-aspartate (NMDA) antagonists which block the toxic effects associated with excess glutamate thereby regulating glutamate activation in the brain. They slow the progression of symptoms associated with moderate to severe AD. NMDA antagonists can be used in combination with a cholinesterase inhibitor.
- Commonly prescribed NMDA antagonists include Namenda® (memantine) and Namzaric® (combination of memantine and donepezil). These FDA-approved drugs are prescribed to treat moderate to severe AD.
