Many children with asthma in the UK are receiving inappropriate treatment, research suggests.
Asthma affects about a million children in the UK
An analysis of UK prescribing data between 2000 and 2006 by Australian researchers suggests some GPs ignore official guidelines.
They found many children were still given syrups or drugs for asthma, which come with a health warning from the British Thoracic Society (BTS).
The study features in the journal Archives of Disease in Childhood.
Around a million children in the UK have asthma, and the condition results in many thousands of hospital admissions a year.
It is thought that up to 30% of GP consultations among children aged five to 15 are due to asthma.
BTS guidance, updated in 2005, discourages the use of bronchodilator syrups designed to open up the airways, because their effect is not very well targeted, and their impact on controlling symptoms can be limited.
But the researchers, from Sydney Children's Hospital, found although prescriptions for this type of medication fell by 60% from 2000 to 2006, 121,000 were still written in 2006.
The study also found that the total number of prescriptions for long acting beta agonists (LABAs) almost doubled - despite concerns about their effect in children.
The percentage of prescriptions for combination inhalers, containing steroid and a LABA, also rose seven-fold.
But the BTS guidance recommends that combination inhalers should be used only when appropriate dose steroid inhalers fail to control the asthma adequately.
And, according to the researchers, persistent asthma accounts for only 5% to 10% of childhood asthma.
Dr John Moore-Gillon, president of the British Lung Foundation, said: "The management of asthma in children has improved greatly over the past two decades, but this research indicates there is still some way to go.
"The authors acknowledge that there may be some limitations to the reliability of their results, but they certainly suggest that significant numbers of children may still not be getting the optimum treatment."
Victoria King, research development manager at the charirty Asthma UK, said: "Getting the right treatment for asthma patients is vital and we advise parents of children on combination inhalers to check with their GPs at their next asthma review, to ensure the GP is prescribing in accordance with BTS guidelines."