Warning on child heart drug doses

Children with congenital heart failure may be at risk from discrepancies in doses of a heart drug designed for adults, researchers have warned. The amount and formulation of captopril vary widely across the UK when it is given to children, a study shows - and may mean the amount given is incorrect.

The drug relaxes the blood vessels, relieving pressure on the heart. The study, by Glenfield Hospital in Leicester, appears in Archives of Disease in Childhood.

The findings are based on survey returns from pharmacies linked to, or located in, 13 children's specialist heart centres and 13 large referring hospitals. Around 1,000 children are prescribed the drug. But it is licensed only for use in adults and is manufactured as a tablet, which many children are either unable or unwilling to swallow. The drug must therefore either be crushed and water added, or obtained from a "specials" manufacturer in liquid form.

The survey results showed that only four pharmacies dispensed captopril tablets for crushing and dissolving in water. The other 22 used nine different liquid formulations of the drug, which came from a variety of sources. Three of the liquid formulations came from specials manufacturers, one from an NHS manufacturing unit, four were prepared "in-house" and one was imported from Australia.

Three hospitals recommended different formulations for use after discharge from those that had been used while the child was an inpatient. Only three specialist centres used the same liquid formulations as their referring hospitals; 10 others used completely different formulations. The stated shelf life of the formulations varied from a couple of weeks to several months.

But with one exception, the time limit was not confirmed by hard data.

The researchers said it was common practice to use different licensed formulations of a drug interchangeably where comparative data was available - but no such data was available for captopril in children. They said failure to use a standard formulation could mean that some children were not getting effective medication - and that their health could be compromised as a result.

Lead researcher Dr Hitesh Pandya said: "It is clear from our survey that further research is needed to establish an optimum formulation of liquid Captopril for use in children. In the short term, pharmacists working in hospitals and the community need to ensure that children are given the same formulation of Captopril wherever it is dispensed. The long term solution is for the pharmaceutical industry and regulatory authorities to work together to develop an optimum formulation of liquid Captopril."

Judy O'Sullivan, a cardiac nurse at the British Heart Foundation, said captopril was effective at controlling the symptoms of heart failure. She said: "This study highlights the need for specific research into children with heart failure, in order to guide doctors treating them so they enjoy the maximum quality of life that their condition allows. More evidence on the best way to treat children with heart failure would in turn provide clear guidance to doctors in prescribing these drugs, to help start to tackle the variations highlighted in this study."