Called memantine, the drug has long been sold in Germany and many U.S. families out of options try to buy supplies overseas via the Internet.
Now armed with Food and Drug Administration approval, U.S. marketer Forest Laboratories will sell memantine here under the brand name Namenda, for patients with moderate to severe Alzheimer's symptoms.
Forest said the drug should be on pharmacy shelves in January.
Memantine doesn't offer miraculous benefits. The FDA's scientific advisers, in evaluating the drug last month, worried that memantine's debut could give false hope to families of the most severely ill.
In studies, some patients given memantine have experienced improvements in memory and thinking skills. But for the vast majority the drug instead slows the pace of deterioration, letting patients maintain certain functions a little longer. For example, the drug helped some patients maintain the ability to go to the bathroom independently for six more months, a benefit caregivers called very important.
It's an important step because memantine is the first option for advanced stages of Alzheimer's. The nation's four other Alzheimer's medications — Aricept, Exelon, Reminyl and Cognex — work in early stages of the disease.
And those drugs work very differently than memantine. They delay the breakdown of a brain chemical called acetylcholine that is vital for nerve cells to communicate. Memantine, in contrast, blocks excess amounts of another brain chemical, called glutamate, that can damage or kill nerve cells.
That means for the first time, doctors could prescribe combinations of drugs in hopes of better results.
About 4 million Americans have Alzheimer's, and a million of them are believed to suffer severe symptoms.
By Lauran Neergaard