Washington ? Americans with advanced Alzheimer’s disease soon can try the first treatment proved effective for late stages of the mind-robbing illness.

Memantine should be on pharmacy shelves by January under the brand name Namenda, its marketer says. The drug has been sold for two decades in Germany, desperately sought by many U.S. families since word of its promise began spreading last year.

It was approved Friday by the Food and Drug Administration.

The marketer, Forest Laboratories Inc., says it has been getting more than 1,000 calls a month from people waiting to buy it. Others have been buying supplies overseas via the Internet.

Memantine does not offer miraculous benefits, said the FDA, worried about giving families false hope.

The drug can delay worsening from Alzheimer’s, however, allowing people to maintain functions such as going to the bathroom independently for a few months longer.

It’s the first option specifically for people with moderate to severe Alzheimer’s symptoms.

Perhaps more importantly, memantine works on a different brain chemical than the other four drugs. That means for the first time, doctors can combine different Alzheimer’s therapies in hopes of better results.

Today, some families import memantine from Europe for prices ranging from $147 to $240 for a month’s supply. Forest Laboratories, which licensed the drug from German maker Merz Pharmaceuticals, refused to say whether U.S. prices would be similar, saying it was not yet decided.