Antidepressants such as Paxil and Prozac should come with strong warnings that they raise the risk of suicidal thoughts and behavior in some children and teen-agers, a U.S. advisory panel concluded on Tuesday.

The U.S. Food and Drug Administration’s panel of outside experts voted 15-8 to recommend warnings on the drug labels set off in a “black box,” the strongest type of warning the government uses for prescription drugs.

Evidence from two dozen clinical trials of nine of the newest antidepressants showed children treated with the drugs were more likely to report suicidal thoughts or actions, panel members concluded. No suicides occurred during the trials.

“The purpose is to put physicians on notice that this group of medicines can cause problems,” said panel member Dr. James McGough, a child and adolescent psychiatrist from Los Angeles.

Robert Gibbons, a panel member and statistician from the University of Illinois-Chicago, stressed the risk was “very small.”

An FDA analysis concluded two or three out of every 100 young people treated with antidepressants might be at higher risk of suicidal behavior. In studies, worrisome actions ranged from writing a suicide note to attempting an overdose.

Any message in a black box would need to appear prominently in advertisements for the medicines, FDA officials said.

Prozac maker Eli Lilly said in a statement it “shares the concerns expressed by some committee members that (a black box) could discourage the use of appropriate treatment.”

Lilly and other manufacturers promised to work with the FDA to decide how best to warn doctors, parents and patients and stressed the drugs’ potential to prevent suicide.

“When people with depression are left untreated, 15 percent will actually commit suicide,” Lilly said.

ALL NINE DRUGS STUDIED

The panelists said safety concern applied to all nine drugs studied, including Prozac, GlaxoSmithKline Plc’s Paxil and Wellbutrin, Pfizer Inc.‘s Zoloft, Forest Laboratories Inc.‘s Celexa, Wyeth’s Effexor, Solvay SA’s Luvox and Akzo Nobel NV’s Remeron were also reviewed.

Bristol-Myers Squibb’s Serzone was also included, but the company discontinued the drug earlier this year.

The black box warnings should also appear on older antidepressants such as tricyclics, the panel said.

Data on suicidal behavior varied among drugs, but “we are unable to conclude any single agent is free from risk at this time,” said Dr. Lauren Marangell, a panel member and psychiatrist at Baylor College of Medicine in Houston.

The black box should also convey results from studies of drugs that failed to show effectiveness in children, some panelists said. Only Eli Lilly and Co.‘s Prozac has been proven effective and is FDA-approved for treating pediatric depression.

About 7 percent of antidepressant prescriptions are written for children, FDA officials said.

The FDA first became aware of a possible link to suicidal behavior in May 2003. Critics charge the agency was slow to act and instead chose to discount the findings of one of its own researchers.

In March 2004 the FDA advised doctors and parents to watch for signs of worsening depression or suicidal thoughts in patients taking the newer antidepressants.

But British authorities had already told doctors last year to avoid prescribing most antidepressants to children because of worries over possible suicidal behavior.

The FDA has committed to updating the drug labels, but has not said when officials will make a final decision. The agency usually follows the advice of its advisory panels.