At present, no treatment can stop Alzheimer's disease (AD). However, some medicines have been able to slow the progression of the disease.

FDA-Approved Drugs

Cholinesterase Inhibitors

Cholinesterase inhibitors are prescribed for the treatment of mild to moderate AD. They may help delay or prevent symptoms from becoming worse for a limited time and may help control some behavioral symptoms. The medications are: Razadyne® (galantamine), Exelon® (rivastigmine), Aricept® (donepezil), and Cognex® (tacrine).

Cholinesterase is an enzyme that breaks down the neurotransmitter acetylcholine. The use of cholinesterase inhibitors in Alzheimer's disease was originally trying to increase the action of acetylcholine. Later it was found that cholinesterase inhibitors can also reduce the level of beta amyloid (reference).

NMDA Antagonists

The drug approved in this category is Namenda® (memantine), prescribed for the treatment of moderate to severe AD. NMDA (N-methyl D-aspartate) antagonists block a special class of ion channels called NMDA channels which play a critical role in the formation of memory. Opening of NMDA channels allows the entry of calcium ions into the cell. Excessive calcium ions are toxic to the cell. NMDA antagonists can reduce such toxicity.

Cholesterol-lowering Drugs

Dozens of reports have confirmed that cholesterol-lowering drugs such as statins can reduce the risk of AD.  It was further shown that low cholesterol reduces the production of beta amyloid (see Cholesterol and ApoE).

Drugs Under Development

Target Secretases

Secretases are the enzymes which cleave the amyloid precursor protein (APP) into the toxic beta amyloid. By modifying the way secretases work may reduce the production of beta amyloid. An example is Flurizan (R-flurbiprofen) which is currently in clinical trial.

Block Aggregation of Beta Amyloid

The toxicity of beta amyloid increases as they clump together. NC-758 is a drug trying to block the aggregation of beta amyloid. It is currently under phase III clinical trial.

Beta Amyloid Vaccines

Researchers are developing vaccines to mobilize the immune system to fight against beta amyloid. A trial that began in the fall of 2001 was later stopped because inflammation unexpectedly developed in the brains of some of the participants.