One class of drugs used to prevent wheezing and shortness of breath in people with asthma may increase kids' risk of being hospitalised for an asthma attack, according to a new analysis from the US Food and Drug Administration.
However, researchers said, it's possible that when the drugs, called long-acting beta-agonists or LABAs, are used in combination with inhaled corticosteroid medications, that extra risk disappears.
"These studies confirm our recommendations at the FDA that are already on drug labels for children and adolescents to use inhaled corticosteroids and LABAs together in one asthma product," said Dr Ann McMahon, who led the study.
Asthma rate climbing
But, she added, the researchers weren't completely convinced from the data they had that inhaled corticosteroids take away all extra risk.
According to the Centres for Disease Control and Prevention, seven million children in the US have asthma(about 9%) and the rate has been climbing steadily in recent years.
Some kids and adults with asthma are prescribed LABAs to relax muscles around the airway and prevent symptoms like wheezing. But there's also evidence that long-term use of the drugs may slightly increase the risk of sudden serious symptoms.
LABAs are also used by people with chronic obstructive pulmonary disorder, or COPD.
Risk greatest in youngest
The FDA report combines safety data from over 100 studies including about 60,000 people with asthma. The original trials were done by companies that market LABAs.
The drugs include Merck's Foradil and GlaxoSmithKline's Serevent.
Compared to all patients who didn't take LABAs, adults and kids who were prescribed the drugs were 27% more likely to end up in the hospital, or in rare cases die or require intubation, because of an asthma attack.
That extra risk was greatest in the youngest study participants. Kids between age four and 11 who were taking a LABA were 67% more likely to have an asthma-related hospitalization than those who weren't getting the medication.
Combined products for kids
That means that over a one-year period, there would be an extra three hospitalisations for every 100 kids taking LABAs.
A small number of people of all ages who were regularly taking an inhaled corticosteroid together with a LABA didn't seem to have any extra risk of hospitalisation, according to the report published in Paediatrics.
"Although we were able to be somewhat reassured... it was a small enough sample that we didn't feel entirely confident, and we need to have further analysis," McMahon told Reuters Health.
The finding of an extra hospitalization risk in people taking LABAs alone isn't new. Last year, after other research suggested that risk, the FDA began requiring drug makers to write on LABA labels that the drugs should not be used without a long-term asthma control medication like an inhaled corticosteroid.
Some asthma medications, including GlaxoSmithKline's Advair and AstraZeneca's Symbicort, contain both a LABA and corticosteroid. The FDA recommends such combined products for kids with asthma.
LABA not prescribed alone
"The thing that's new in this paper... is they've highlighted the fact that younger children may have a higher risk when taking a LABA alone," said Dr Scott Weiss, as asthma researcher from Harvard Medical School in Boston who was not involved in the report.
Weiss reported financial ties to the drug company Novartis, and was formerly linked to GlaxoSmithKline and AstraZeneca.
McMahon said the analysis wasn't designed to examine the reason for extra risks due to LABA use in kids, and didn't want to speculate. But Weiss said it could be related to their smaller airways.
He agreed that it's important for future studies to look directly at the issue of serious attacks in LABA users to determine the underlying cause behind those attacks – and whether they're directly caused by the medications themselves.
Still, he told Reuters Health, "Nobody is really prescribing a LABA on its own – that's basically off the market."
(Reuters Health, October 2011)