Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline also occurs in other neurological conditions, such as Parkinson's disease, Lewy body dementia, vascular dementia, and frontotemporal dementia.

View the Comparison Table: Drugs for Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

The motor symptoms of Parkinson's disease (PD) are caused primarily by degeneration of dopaminergic neurons in the substantia nigra. The nonmotor symptoms of the disease are thought to be caused by degeneration of other neurotransmitter systems. No disease-modifying drugs are available for treatment of PD.

The motor symptoms of Parkinson's disease (PD) are caused primarily by degeneration of dopaminergic neurons in the substantia nigra. The nonmotor symptoms of the disease are thought to be caused by degeneration of other neurotransmitter systems.

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive loss is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

The FDA has approved Namzaric (Forest), a fixed-dose combination of extended-release (ER) memantine (Namenda XR), an NMDA-receptor antagonist, and donepezil (Aricept, and generics), an acetylcholinesterase inhibitor, for treatment of moderate to severe Alzheimer's type dementia in patients previously stabilized on both drugs. The patent for Namenda has recently expired and generic formulations of memantine 5- and 10-mg tablets have been approved.

Cholinesterase inhibitors are now used routinely in patients with dementia. Rivastigmine transdermal system (Exelon Patch - Novartis), a patch formulation of the cholinesterase inhibitor rivastigmine tartrate, has been approved by the FDA for treatment of mild to moderate dementia associated with Alzheimer's or Parkinson's disease. An oral formulation of rivastigmine tartrate has been available in the US since 2000,2 but gastrointestinal adverse effects possibly related to rapidly rising serum concentrations have limited its use.