Memantine

Glutamate is a chemical messenger that is important for many brain functions, including learning and memory. In Alzheimer's, certain disease processes cause too much glutamate activity. Excess glutamate causes irregular activity and damage in nerve cells that interact with the chemical messenger.

Memantine (Namenda) is a medicine that limits glutamate-cell interactions. Memantine may help slow the decline in memory and thinking skills. It also may play a role in protecting nerve cells.

Memantine is approved to treat moderate to severe Alzheimer's disease. It's usually taken as a pill or liquid twice a day or as an extended-release pill once a day.

Side effects may include dizziness, headache, confusion, hallucinations, agitation and constipation.

The FDA also has approved a combination of donepezil and memantine (Namzaric). It's taken as an extended-release pill once a day.