Memantine hydrochloride was originally synthesized in 1963 at Eli Lilly & Co as an antidiabetic agent but was found to be ineffective in lowering elevated blood sugar. Merz & Co in Germany took it over and, a decade later, showed its effectiveness in Parkinson disease. In 1989, therapeutic action of memantine was shown to be due to antagonism of N-methyl-D-aspartate receptors (Kornhuber et al 1989), and it was launched in Germany for the treatment of dementia. Further clinical trials were conducted on its use in Alzheimer disease between 1995 and 2000, and the drug was approved in the European Union in 2002. The FDA approved it for the treatment of moderate to severe Alzheimer disease in 2003. It is marketed in the United States under the trade name of “Namenda” (Forest Laboratories).