Cigarette smoking is at its lowest level in a survey of teenagers and use of illicit drugs has been declining, but continuing high rates of abuse for prescription painkillers remain a worry, the government reported Monday.

The decline in drug use is "quite remarkable news," Dr. Nora D. Volkow, director of the National Institute on Drug Abuse, said in issuing the agency's annual survey of drug use by children in grades eight, 10 and 12.

But she added that "prescription drugs are very powerful medicines that are effective when used properly and with a doctor's supervision. Using these drugs without a prescription is dangerous. It's imperative that teens get this message."

She also raised concerns about increased use of inhalants and Lloyd Johnston, director of the study, noted that declines in smoking seem to have stopped among eighth-graders, a finding that could raise concerns in the future, he said.

Karen Tandy of the Drug Enforcement Administration warned of the increased availability of drugs.

"The drug dealers that used to be in the back alley are now in the bedrooms of our children because they come to them through the Internet," she said.

In the study, 9.5 percent of 12th-graders reported using the painkiller Vicodin and 5.5 percent reported using OxyContin in the past year. Long-term trends show a significant increase in the abuse of OxyContin from 2002 to 2005 among 12th-graders.

Also of concern is the significant increase in the use of sedatives and barbiturates among 12th-graders since 2001.

Overall, however, the report had good news, particularly about cigarette smoking.

It cited a 19 percent decline over the past four years in the use of any illegal drug in the month before the survey was done.

"Teens are getting the message. Drugs are harmful and will not only hurt their brains and bodies, but also damage their futures," said John P. Walters, director of the White House's Office of National Drug Control Policy.

In the survey, teens were asked about use of drugs, tobacco and alcohol in their lifetime, in the month before the survey and in the year before the survey.

Lifetime use of cigarettes declined 2 percent among eighth-graders, decreased 1.7 percent among 10th-graders and declined 2.8 percent among 12th-graders, according to the Monitoring the Future survey done by the University of Michigan. The study surveyed 49,347 students in 402 public and private schools.

Smoking is a concern because cigarette use is often seen prior to use of other drugs.

Other findings included:

—Use of alcohol during the year before the survey was down 2.7 percent among eighth-graders; down 1.5 percent among 10th-graders; and down 2.1 percent among 12th-graders.

—Use of methamphetamine during their lives fell 1.2 percent among 10th-graders and fell 1.7 percent among 12th-graders.

—Between 2001 and 2005, lifetime and last-year use of steroids declined for all grades.

—Lifetime use of marijuana fell from 2001 to 2005 for all grades and past-month use declined for 8th- and 10th-graders.