June 16 (HealthDay News) -- The U.S. Food and Drug Administration is cautioning physicians that certain types of antipsychotic drugs can boost the death risk of seniors with dementia.

Doctors sometimes use antipsychotics to help treat behavioral problems in demented patients.

But from now on these older, so-called "conventional" antipsychotics -- which include drugs such as thorazine and prolixin -- will carry a new black box warning alerting physicians of the danger, FDA officials announced Monday.

"We issued letters to all the manufacturers of antipsychotic drugs, both conventional and atypical, requiring them to update their labeling with new language for a box warning about an increased risk of death in elderly patients with dementia," Dr. Thomas Laughren, director of the FDA's Division of Psychiatry Products at the Center for Drug Evaluation and Research, said during an afternoon teleconference.

This is a new warning for conventional antipsychotics, but it is not new for another class of the medications, called atypical antipsychotics. Back in 2005, the FDA ordered warning labeling for those medications, which include newer drugs such as Zyprexa and Risperdal. That labeling warned of a higher risk for heart attack and pneumonia for elderly patients with dementia who received atypical antipsychotics.

This new black box warning for older, conventional antipsychotics is one of the first uses by the agency of the Food and Drug Administration Amendments Act of 2007, which gives the FDA authority to mandate drug warnings, something they could only request before.

According to Laughren, the FDA based its 2005 decision on a review of studies comparing their use to a placebo. At the time, a lack of evidence prevented the agency from extending the warning to conventional antipsychotics, Laughren said.

However, since then, observational studies have appeared that indicate that conventional antipsychotics carry the same risk, he said. "The data we have for observational studies are not ideal, so we struggled with this decision, but in the end decided that the data were strong enough to extend the warning to all drugs in this class," he said.

When looking at the data involving atypical antipsychotics, the FDA found that over 10 weeks, roughly 4.5 percent of patients with dementia taking these drugs died, compared with 2.6 percent of patients receiving a placebo, Laughren said.

Laughren noted that all these patients were very ill in their 80s and in nursing homes. The deaths appeared to be mostly from cancer or infections such as pneumonia.

One study by Canadian researchers, published in May in the Archives of Internal Medicine, found that elderly patients with dementia given atypical antipsychotics were 3.2 times more likely than individuals who had received no antipsychotic therapy to be hospitalized or to die during 30 days of follow-up.

Conventional antipsychotics, as well as atypical antipsychotics, are not approved for use in elderly patients with dementia, Laughren noted.

"Patients with dementia often have behavioral symptoms as well. They can have psychotic symptoms, such as delusions and hallucinations, they can be agitated, aggressive and at times violent, and antipsychotic drugs are sometimes used in treating these behavioral symptoms," Laughren said.

"We are not telling physicians that they absolutely cannot use these drugs in this setting," he added. "What we want to do is make them aware of this risk. This is something we hope they would discuss with the families and caregivers so they can understand that there are risks to using these drugs."

Both conventional and atypical antipsychotics are dopamine receptor agonists that work by blocking the action of dopamine in the brain. The primary differences between them are side effects, which are fewer among the atypical antipsychotics.

SOURCES: June 16, 2008, teleconference with Thomas Laughren, M.D., director, Division of Psychiatry Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration