Patients in the moderate to severe stages of Alzheimer's disease may benefit from a new drug available in pharmacies this month.

The drug memantine, approved by the U.S. Food and Drug Administration in October 2003, has been shown to slow the disease's decline, allowing patients to perform some functions of daily living longer. The Alzheimer's Disease Center at Baylor College of Medicine in Houston participated in a clinical trial on the drug from 2001 to 2002.

"Memantine slows functional loss, helping people retain their functional abilities even when they are in the severe stages of the disease," said Dr. Rachelle Doody, a professor of neurology and director of the Alzheimer's Disease Center at BCM. "In some cases it may delay the time until a patient enters a nursing home, or requires more hands-on assistance from a caregiver."

Memantine is the first in a class of drugs that protects the brain's nerve cells against excess amounts of the chemical glutamate, which overexcites one of the transmitter systems in the brain. When the transmitter system is over-activated, it can lead to the death of brain cells. The drug works on a different system of the brain than current drugs for Alzheimer's, called cholinesterase inhibitors. Some studies have shown that combining both types of drugs may be an effective treatment for Alzheimer's. No drug stops the progression of Alzheimer's disease.

When patients with Alzheimer's reach the moderate stages of the disease, they uniformly have problems with the complex activities in daily life, like managing finances or using telephones. As the disease progresses to severe stages, they may lose many of the abilities that most people learn in early childhood and need help dressing, bathing, eating and walking. Stress on the caregiver increases substantially during this stage, because the patient needs more help to care for himself or herself.

"Severe Alzheimer's disease takes all different forms," Doody said. "I can see a severe patient who needs help with dressing, and could never put together a proper meal, but still likes to go out to dinner, enjoy events with family and travel. So severe disease doesn't mean the patient is inactive, or untreatable."

Until more new treatments for severe Alzheimer's are approved, early diagnosis is key.

"People need to know that Alzheimer's disease can be diagnosed, and that diagnosing it early and treating it early makes a difference," Doody said. "Many patients are never diagnosed, or are diagnosed too late because families and physicians do not notice the problems until it's very advanced."