Liquid medicines commonly given to premature babies and infants contain potentially harmful substances - and sometimes at levels above those recommended for adults - reveals a study published ahead of print in the Fetal & Neonatal Edition of Archives of Disease in Childhood.
Babies born early have a much higher risk of a range of diseases and complications associated with their prematurity than babies born after a normal length pregnancy. Liquid medicines are the usual formulation used to treat them as babies cannot swallow pills.
Many contain agents, known as excipients. These are used to ease the administration, absorption or preservation of the active substances or improve the taste and appearance of the medicine.
Rigorous checks are carried out on prescription medicines to ensure their quality, safety, and effectiveness. But most of these checks are carried out in adults, and there are few data on the safety of specific excipients, especially in such young patients, say the authors.
They assessed the type and content of liquid medicines given to 38 babies for whom all drug records were available. All the babies weighed under 1500 g at birth, and had been born after 30 or fewer weeks of pregnancy. They were all admitted between June 2005 and July 2006 to a neonatal intensive care unit at one English hospital.
The babies were treated for between 2.5 and 9 weeks, and given a range of treatments, from iron and vitamin drops to Furosemide and Dexamethasone.
During this time, they were regularly exposed to 20 different excipients, including ethanol found in iron and Furosemide and propylene glycol (found in Dexamethasone), chemicals that have the potential to cause nerve damage.
Seven of them had severe lung disease as a result of their prematurity, and these babies were exposed to higher levels of excipients than the babies without this problem.
Exposure to ethanol ranged from 0.2 ml to 1.8 ml per week, equivalent to 1 to 7 units of alcohol, while exposure to sorbitol Dexamethasone and iron ranged from 0.1 to 3.5 g/kg/week.
The recommended maximum intake of sorbitol for adults is 20 g/day. When calculated according to the baby's weight, this level was exceeded in 18 babies for at least one week.
All babies given Dexamethasone exceeded the recommended levels of propylene glycol, which is about two thirds as strong as ethanol.
The UK Food Standards Agency has recommended the removal of the colourant Ponceau 4R, because of concerns about its effect on neurodevelopment and behaviour. This agent was found in the iron formulation given to the infants.
The authors point out that children's medicines have to cater for a wide age range, making it difficult for manufacturers to tailor their products for each age group. The inclusion of some excipients is also a necessity.
But they conclude: We feel it is important that the [medicines regulators not only ensure that all manufacturers provide detailed labelling of the excipient content of their products but all lead action to determine whether existing practice constitutes a risk, and if so, how this might be dealt with.