(HealthDay)—The amount of corticosteroids delivered by nebulizers in children with asthma differs from the prescribed dose, the amount varying with drug formulation, according to research published online Nov. 24 in Respirology.

Chris O'Callaghan, of the University of Leicester in the United Kingdom, and colleagues used filters to capture and measure the amount of corticosteroid delivered by nebulizers when inhaled by children with and compared it with the prescribed dose of drug.

The researchers found that the children with asthma using nebulizers would have inhaled varying proportions of the prescribed dose of fluticasone propionate (13 percent), beclomethasone dipropionate (21 percent), and flunisolide (25 percent). The percentage of the dose inhaled that was more likely to reach the lungs was even lower for fluticasone propionate (5 percent), beclomethasone dipropionate (8 percent), and flunisolide (16 percent). The inter-subject variation coefficient of the dose inhaled was greater for fluticasone propionate (34 percent) and beclomethasone dipropionate (45 percent) suspensions than for flunisolide suspensions (9 percent).

"Our study confirms that the prescribed dose bears little resemblance to the proportion of drug actually inhale and that this is largely dependent on the formulation of the drug," the authors write.

Two authors disclosed to pharmaceutical companies.