Safety fears about asthma drug after young children have serious side effects

Children as young as three have suffered traumatic side effects from a blockbuster asthma drug now under review by the UK medicines regulator.

Families say asthma sufferers, many of whom are children, are not properly warned about the risks of the commonly prescribed drug montelukast.

It has been associated with night terrors, depression, and rarely, hallucinations or suicidal behavior.

The Medicines and Healthcare products Regulatory Agency (MHRA) confirmed this weekend that it was assessing the risks of the drug after identifying “further concerns”.

Tanya Hinder, from British campaign group Montelukast, said: “Those affected have reported uncontrollable aggression, children attacking family members and suffering from very intrusive thoughts. Tragically, there have also been suicide attempts and reports.”

The UK campaign group for the drug, which represents almost 3,500 members, is campaigning for more prominent warnings, stricter controls and support for those affected. It says patients should consult a doctor first if they have any concerns.

Graham and Alison Miller, whose son Harry, an asthmatic, took his own life while taking the drug in February 2018 at the age of 14, are among the families calling for action. They learned about the possible side effects of montelukast two years after their son’s death and want his inquest reopened.

Jenny Llewellyn, 33, a teaching assistant at a nursery, said her daughter Lottie was prescribed the drug when she was just three. It seemed to bring about abrupt changes in her behavior. “It was all doom and gloom,” Llewellyn said. “She went to bed crying and woke up crying.”

The groundbreaking asthma and allergy drug was launched by pharmaceutical giant Merck in 1998. It prevents the airways from narrowing and helps prevent asthma attacks. The drug’s side effects, including behavioral and mood changes, are listed in the patient information sheet, but campaigners say the warnings should be printed on the packaging and highlighted by health professionals.

There were 4.3 million montelukast prescriptions in England in 2022/2023, worth £6.69 million. The campaign group estimates that around 350,000 patients are prescribed the drug in England, including more than 35,000 children, based on an analysis of NHS data. It can be given to babies as young as six months old.

In the US, the drug has a black box warning since 2020, the highest safety alert drugs can be assigned by the FDA. The agency has highlighted animal studies that suggest the drug can cross the blood-brain barrier, a membrane that acts as a filter and keeps out harmful substances and pathogens.

On February 21, New York Attorney General Letitia James wrote to the FDA, calling on the country to take “immediate action” against the drug, which is sold under the brand name Singulair. She said “tragic mental health events” involving children continue to be reported.

The MHRA said clearer warnings had been included in product information about the risk of neuropsychiatric effects following a European review in 2019. It also highlighted at the time the risks of neuropsychiatric reactionswith some side effects reported more frequently in children.

The agency said: “We are carrying out a further review to consider new data on the risk, indicators of lack of awareness among patients, carers and healthcare professionals and whether further regulatory action is required.

“We are now in the final phase of our investigation. We continue to closely monitor reports of suspected neuropsychiatric adverse reactions to montelukast and have initiated our current review after identifying further concerns.”

Organon, a Merck spin-off responsible for montelukast in Britain, said: “Nothing is more important to Organon than the safety of our medicines and the people who use them. We continuously monitor safety.

“We are confident that, working with the MHRA, we have provided healthcare professionals and patients with full and appropriate information about the safe and effective use of monetelukast.”

Dr. Andy Whittamore, clinical lead at Asthma+Lung UK, said: “Montelukast is generally a very safe medicine. It is important that doctors explain the possible side effects.”