Asthma inhalers can stunt the growth of children, research has shown.
During the first year of treatment, the widely used remedies cut growth rates by about half a centimetre, said scientists.
But they and other experts stressed that slight loss of growth was a small price to pay for protection against potentially lethal asthma attacks.
Evidence also suggested that the effect could be minimised by using lower doses of the drugs.
Scientists reviewed trial data on more than 8,000 young people aged 18 and under with mild to moderate asthma.
The research focused on corticosteroid inhalers which are prescribed as first-line treatments for both adults and children with persistent asthma.
Writing in the Cochrane Library, a collection of publications designed to inform health care decision making, the team assessed effects of the drugs on children’s growth.
Lead author Dr Linjie Zhang, from the Federal University of Rio Grande in Brazil, said: “The evidence we reviewed suggests that children treated daily with inhaled corticosteroids may grow approximately half a centimetre less during the first year of treatment.
“But this effect is less pronounced in subsequent years, is not cumulative, and seems minor compared to the known benefits of the drugs for controlling asthma and ensuring full lung growth.”
The review looked at 25 trials involving 8,471 children and teenagers up to 18 years old. It found that as a group, corticosteroids suppressed growth rates when compared with inactive placebos or non-steroidal drugs.
Fourteen of the trials, with 5,717 participants, reported growth over the course of a year. Use of asthma inhalers was found to cut half a centimetre from an average annual growth rate of six to nine centimetres.
A second review by the same researchers examined data from 22 trials in which children were treated with low or medium doses of inhaled corticosteroids.
Only three trials followed 728 children for a year or more. In these trials, reducing inhaler doses by about one puff a day improved growth by a quarter of a centimetre per year.
Seven inhaled corticosteroid (ICS) drugs are currently marketed around the world: beclomethasone, budesonide, ciclesonide, flunisolide, fluticasone, mometasone and triamcinolone.
Of these, ciclesonide, fluticasone and mometasone are newer and supposedly safer.
Experts commenting on the research said it was important to put the findings in perspective and urged parents not to stop making asthma inhalers available to their children.
Samantha Walker, director of research and policy at the charity Asthma Research UK, said: “Half a centimetre in growth is a small price to pay for medicine which may save your child’s life.
“Uncontrolled asthma can substantially increase the likelihood of asthma attacks, hospitalisation and even death and we know that inhaled steroids, taken regularly, significantly reduce the likelihood of these events happening.
“For a long time now people with asthma have told us they fear the side effects of taking asthma medicines but the good news is this evidence shows only a relatively minor impact from inhaled corticosteroids. No parent should therefore stop their children taking these lifesaving medicines.”
Jon Ayres, Professor of Environmental and Respiratory Medicine at the Institute of Occupational and Environmental Medicine, University of Birmingham, said: “These studies confirm what many have suspected, that inhaled steroids can suppress growth in children.
“However, the effect seems to be small and non-cumulative and many may consider this a risk worth taking compared to the alternative which is poorly controlled, and therefore potentially life-threatening, asthma.”