Some common cold and flu pills taken at night may increase the risk of seizures in young children, according to a worrying study uncovered today.
Scientists in South Korea analyzed data on children who had visited a emergency room with a seizure.
They found that those taking prescription drugs, called “first-generation antihistamines,” were 22 percent more likely to cause the medical episode.
This risk was 31 percent among children between six months and two years of age.
Experts warned today that doctors should be cautious when prescribing these anti-allergy drugs, often used to treat colds in young children.
Scientists in South Korea analyzed data on children who had visited an emergency room with a seizure and found that those on prescription drugs called “first-generation antihistamines” were 22 percent more likely to have the medical episode.
Antihistamines decrease the production of histamine, a substance that causes runny nose, watery eyes, and sneezing.
Some cold and cough remedies also contain antihistamines.
Unlike newer antihistamines, older first-generation medications can often make users drowsy because they easily pass from the blood into the brain.
According to NHS guidelines, only children over the age of six should be prescribed diphenhydramine, a type of first-generation antihistamine.
The study identified 11,729 children, born between 2002 and 2005, who had visited an emergency department for a seizure.
Researchers at CHA University School of Medicine in South Korea found that of these children, 3,178 had taken antihistamines in the period before a seizure, suggesting the drugs increased the risk.
One third (31 percent) of the observed seizures occurred in children between six months and two years, and less than half (45 percent) occurred in children between two and six years.
The scientists also found that children were at higher risk if they had been prescribed the drugs up to 15 days earlier.
Writing in the diary JAMAThey said: ‘Because first-generation antihistamines can cross the blood-brain barrier, their effects may extend beyond drowsiness and sleep to markedly influence brain wave activity.
‘Therefore, caution is advised when prescribing these antihistamines to children under two years of age, an age group for which data on drug safety are lacking and first-generation antihistamines are generally not recommended.’
They also suggested that children under six are more vulnerable to seizures than older age groups due to “the development of the blood-brain barrier, which continues to evolve in this age group.”
The scientists added: ‘In infants, incomplete formation of the blood-brain barrier leads to increased permeability and a higher risk of drug penetration into brain tissue.
‘Therefore, antihistamines, which are relatively harmless to adults and older children, could significantly affect infants in a negative way.’
Although researchers found an increased risk of seizures in children who took antihistamines, used in cold and flu medications, the study authors suggest more research is needed.
“The benefits and risks of antihistamine use should always be carefully considered, especially when prescribing H1 antihistamines to vulnerable infants,” they said.
“Further research is needed to elucidate the associations between antihistamine prescriptions and seizure risk,” they added.