A US Food and Drug Administration panel decided on Thursday that two asthma drugs pose serious risks that outweigh their benefits for treating adults and children. They are GlaxoSmithKline PLC’s Serevent and Novartis AG’s Foradil.

On the other hand, Glaxo’s Advair and AstraZeneca PLC’s Symbicort have acceptable safety for asthma patients of all ages, the FDA panel decided.

All four drugs belong to a class of medications known as long-acting beta-agonists, or LABAs, and have been the subject of an ongoing FDA safety review. They help control and prevent airway spasms during asthma attacks. But the drugs have been recently linked to a small but significant increase in the risk of hospitalization and death from asthma.

Consequently, the FDA had recommended restrictions on all four drugs, including that none of them be used to treat asthmatic children. But the panel said Advair and Symbicort should continue to be used with all patients. Serevent and Foradil can still be sold for treating another lung disease, chronic obstructive pulmonary disease.

The companies that manufacture the drugs insist that they are not dangerous, and that there isn’t enough evidence to justify the prohibition of the drugs.

According to the National Institutes of Health, almost one in ten Americans is diagnosed with asthma at some time. The number of children with asthma has more than doubled since the 1980s. According to the CDC estimates, about 20 million Americans have asthma, including 9 million children.

The causes of the disease are not fully understood, but a variety of combined factors is suspected. It appears that certain environmental and genetic factors may only affect asthma when combined. Some studies have linked asthma with the stress of a pregnant woman or with the violence some kids face during their childhood.