A committee of experts today unanimously said Advair, GlaxoSmithKline P.L.C.'s best-selling drug, was safe enough to remain on the market to treat asthma, but declared two other drugs too risky.

The panel convened by the Food and Drug Administration also urged the agency and drug companies to study more carefully whether certain asthma drugs were safe to use in children.

The panel of outside experts had been examining the safety of four asthma drugs - GlaxoSmithKline's Advair and Serevent, AstraZeneca P.L.C.'s Symbicort, and Novartis AG's Foradil. Some data have suggested that these drugs increased the risk of hospitalization and death in asthma patients.

About 22 million people in the United States suffer from asthma, which claims nearly 3,600 lives each year. Children account for nearly one of every three patients.

GlaxoSmithKline, which is based in London but has large operations in Philadelphia, said it welcomed the FDA's decision on Advair, but said its Serevent also remained an important treatment. The company reported U.S. sales of $4 billion last year for Advair alone.

The 27-member panel, comprising pediatricians, asthma specialists and consumer advocates, said overwhelmingly that Advair's benefits outweighed its risks. The panel also said the benefits of AstraZeneca's Symbicort outweighed its risks.

The panel, on narrower votes, made the opposite decision on Serevent and Foradil, meaning it wanted the FDA to reconsider their use by asthma sufferers.

It was an even-narrower vote on Advair and Symbicort on whether they should be used for teenagers and children. An FDA analysis presented at the meeting said the risks were greater in children.

Advair is approved for ages 4 and older, and Symbicort for those at least 12.

Patients should not stop taking any of the medications without consulting their doctors, said John Jenkins, head of the FDA's new drugs office.

Advair and Symbicort combine two drugs, a long-acting beta agonist, which treats spasms, and corticosteroids, which reduce swelling. Serevent and Foradil contain beta agonists only.

The FDA will weigh the committee's recommendations as it decides whether the asthma drugs require stronger labels or should remain on the market. A final decision could take several months.

All the companies have maintained that their drugs were safe.

GlaxoSmithKline's chief medical officer, Ellen Strahlman, said the company had applied for a change in Serevent's label to strengthen warnings that it needed to be taken with a steroid. Some patients need to take the two drugs separately to get the correct doses, she said. Also, a few managed-care plans do not cover the combined product, GlaxoSmithKline said.

London-based AstraZeneca, which has large operations in Wilmington, said it was pleased that the FDA committee agreed that Symbicort was a beneficial product.

The FDA has been studying the safety of long-acting beta agonists, or LABAs, for asthma for several years. In the most recent review, agency scientists analyzed findings from 110 clinical trials involving nearly 61,000 patients. Experts looked for deaths, hospitalizations, and cases in which a patient had to have a breathing tube inserted. The analysis found 20 deaths from asthma complications, of which 16 were in patients taking a LABA-only drug, Serevent.

FDA scientists were divided about what the data meant. One said the benefits of all four drugs were unproved while their risks appeared high. Others said the drugs helped asthma sufferers exercise, sleep through the night, and miss fewer days of work and school, benefits that outweighed the risks.

Several people who testified before the committee said the drugs were necessary.

"If this drug is removed from asthma treatment, it would be a disaster," said Stanley Szefler, a physician from National Jewish Health, a Denver health system with a national reputation for respiratory care. He spoke on behalf of the American Academy of Allergy, Asthma and Immunology. Other medical societies voiced similar sentiments.

Baltimore-area teacher Anne Dorsey went to the meeting with her son Julian, 13, who has severe asthma. The mother told the panel that Julian nearly died from an asthma attack in 2006. But he has done much better since then, after he started taking Advair.

"I've spent a lot of time in the hospital," Julian said. "But when I took Advair, life got a whole lot easier."

Still, committee members were especially concerned about this type of drugs' risks in children. Several members called for a large controlled study on children and adolescents to get better data about the benefits and risks. Some members also worried that African Americans appeared to have more problems with the drugs than other groups.

AstraZeneca global vice president for Symbicort, Cathy Bonuccelli, said the company's data for children and for African Americans showed no increased risk. The company is conducting two trials, including one for safety in African Americans.

Contact staff writer Miriam Hill

at 215-854-5520 or hillmb@phillynews.com.

This article includes information from the Associated Press.