A popular inhaled drug used to treat asthma makes children shorter, a new study has found.
Budesonide, marketed in Australia as Rhinocort and Pulmicort, stunts children's growth, cutting about 1.2cm off their height permanently.
The new research is based on a previous study, which showed that budesonide was safe and effective, but noted that kids taking it were an average of 1.2 cm shorter than those taking other asthma drugs.
The original study examined more than 1000 asthma sufferers aged five to 12. The kids were split into three groups and given budesonide, a non-steroid drug called nedocromil or a placebo.
William Kelly from the University of New Mexico, and his colleagues from several other universities, built on this study, contacting 943 of the original study respondents who were now adults.
They discovered that the children who were given budesonide were still an average of 2.5cm shorter than the other kids.
It was previously thought that children whose growth was stunted by the drug would "catch up" to their peers later in life.
"This was surprising because in previous studies, we found that the slower growth would be temporary, not affecting adult height," researcher Dr Robert Strunk, of Washington University in St Louis, said.
The good news is that while affected kids don't "catch up" to those not taking the drug, they don't fall further behind either.
If your child is taking budesonide, the researchers warn against taking them off the drug without consultation with their doctor.
Strunk says a child's dosage can be reduced if a child's growth is a problem, but says in some serious asthma cases, the drug's effectiveness might be worth the loss of a couple of centimetres of height.
"If a child is not growing as they should, we may reduce their steroid dose," Strunk said. "But we think that the half-inch of lowered adult height must be balanced against the well-established benefit of inhaled corticosteroids in controlling persistent asthma.
"We will use the lowest effective dose to control symptoms to minimise concerns about effects on adult height."
This study was published in the New England Journal of Medicine and was presented at the European Respiratory Society Annual Congress in Vienna, Austria, this week.
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