Commonly used over-the-counter drug taken by millions linked to frightening risk of epileptic seizures in children, study finds

Some commonly used night-time cold and flu pills may increase the risk of seizures in young children, worrying research published today suggests.

Scientists in South Korea analyzed data from children who had a Emergency room with an attack.

They found that prescription drugs, so-called ‘first generation’ antihistamines, were 22 percent more likely to cause a medical episode.

In children between six months and two years old, this risk was 31 percent.

Experts today warned doctors to be careful about prescribing these anti-allergy drugs, which are often used to treat colds in young children.

Scientists in South Korea analyzed data from children who visited an emergency room with an attack. They found that those prescribed medications, called “first-generation” antihistamines, were 22 percent more likely to have the medical episode

Antihistamines reduce the production of histamine, a substance that causes a runny nose, watery eyes, and sneezing.

Some cold and cough remedies also contain antihistamines.

Older, first-generation drugs, unlike newer antihistamines, can often cause drowsiness 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 come to the emergency room with an epileptic seizure.

Researchers from CHA University Medical Center in South Korea found that 3,178 of them had used antihistamines in the period before the attack, suggesting that the drugs increase the risk.

A third (31 percent) of observed attacks occurred in children between six months and two years of age, and less than half (45 percent) occurred in children between two and six years of age.

The scientists also found that children were at greatest risk if they had been prescribed the drugs less than 15 days beforehand.

Writing in the diary JAMAthey said: ‘Because first-generation antihistamines can cross the blood-brain barrier, their effects may extend beyond drowsiness [sleepiness] and drowsiness have a significant impact on brain activity.

‘Therefore, caution is advised when prescribing these antihistamines to children under two years of age. There is insufficient data on the safety of drugs for this age group and first-generation antihistamines are generally not recommended.’

They also stated that children under the age of six are more vulnerable to seizures than older age groups due to ‘the developing blood-brain barrier, which is still evolving in this age group.’

The scientists add: ‘In infants, incomplete formation of the blood-brain barrier leads to increased permeability and a greater risk of the drug penetrating into brain tissue.

‘Antihistamines, which are relatively harmless for adults and older children, can therefore have a negative effect on infants.’

While researchers found an increased risk of seizures in children taking antihistamines, which are used in cold and flu medications, the study authors say more research is needed.

“The benefits and risks of using antihistamines should always be carefully weighed, especially when prescribing H1 antihistamines to vulnerable infants,” the researchers said.

‘Further research is needed to clarify the association between antihistamine prescription and risk of seizures,’ they add.