• Montelukast is commonly prescribed for severe asthma, especially in children, but it can have serious psychological side effects
  • The US FDA issued a warning, but many doctors are unaware of the risks and even prescribe it for coughs and allergies
An asthma drug is being used to treat minor coughs and allergies, despite its potentially serious side effects. Photo: Shutterstock

When Cindy Yin's three-year-old daughter, Chloe, spent weeks trying to shake a wet cough and runny nose in December last year, the Hong Kong mother sought help from a family doctor.

Yin says her daughter was prescribed montelukast, a common asthma drug sold in Hong Kong under the brand name Singulair. Within days, she witnessed a change in Chloe.

"An hour after falling asleep Chloe started crying and screaming and I couldn't calm her. She also had terrible nightmares. But the oddest thing was it seemed like she didn't recognise me," recalls Yin.

This month, the US Food and Drug Administration (FDA) issued a black box warning " the highest level boxed warning " strengthening an existing warning that the drug was linked to depression, sleeping problems, and suicidal thoughts.

Montelukast has been linked to nightmares and other sleeping problems. Photo: Getty Images

While the drug is seen as an effective treatment for severe and potentially life-threatening asthma, the main concern the FDA raised is that it is being prescribed for mild coughs and hay fever. The added warning advises health care providers to avoid prescribing montelukast for patients with mild symptoms, particularly those with hay fever.

"We recognise that millions of Americans suffer from asthma or allergies and rely on medication to treat these conditions. The incidence of neuropsychiatric events associated with montelukast is unknown, but some reports are serious, and many patients and health care professionals are not fully aware of these risks," said Dr Sally Seymour, director of the Division of Pulmonary, Allergy and Rheumatology Products in the FDA's Centre for Drug Evaluation and Research.

Singulair asthma pills. US health regulators are probing a possible connection between Singulair and suicidal behaviour in adults and children. Photo: Getty Images

Yin says she was not told of any potential side effects when Singulair was first prescribed. "It was only when I told my doctor on the second visit that I suspected my daughter was suffering from nightmares that she told me about the side effects. She said that in rare cases, the medication causes nightmares in children and told me to continue administering it. But what I saw that night with my daughter was more terrible than a nightmare."

Dr Lee Tak-hong, a specialist in immunology and allergy at the Hong Kong Sanatorium & Hospital, says Singulair is commonly prescribed for asthma treatment and quite frequently for coughs.

"Hongkongers have a relatively excessive fear of taking steroids (a key treatment for asthma, usually through an inhaler) so non- steroid drugs such as Singulair are often used in their place. In reality, inhaled drugs used correctly are very safe."

Dr Lee Tak-hong is a specialist in immunology and allergy at the Hong Kong Sanatorium & Hospital.

Lee has prescribed Singulair for severe asthma and says while potential serious side effects are rare, the drug should be avoided if there is a history of neuropsychiatric illness, or if symptoms arise while using the drug.

"In my view, it should not be prescribed for hay fever and seldom for cough unless it is a cough variant of asthma. Even then it would not be my first choice of drug," says Lee.

Lee says hay fever symptoms should be treated by finding the cause of the allergy and avoiding it, using a non-sedating antihistamine or nasal steroids, with or without nasal washes. He says allergen-specific desensitisation, a method to reduce or eliminate an organism's negative reaction to a substance or stimulus, should also be considered.

A Singulair asthma pill. Photo: Getty Images

"Treating a cough depends on its cause. It may require inhaled corticosteroids with or without a long acting beta agonist (airway muscle relaxant) if there is associated asthma. Singulair is a useful drug for the management of severe asthma and the new (FDA) boxed warning highlights a known problem," says Lee

He said he had received no complaints about patients experiencing neuropsychiatric symptoms while taking the drug. "Those already taking it should not stop it without speaking to their doctor first," he added.

Dr Adrian Wu, a specialist in allergy and immunology at Hong Kong's Centre for Allergy and Asthma Care, says Singulair is commonly prescribed in Hong Kong. "I rarely prescribe it," he says, noting some children have complained of agitation when taking it.

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Yin says about a month after her daughter's experience, her son " who was just 10 months old at the time " was also prescribed Singulair by the same doctor to treat a cough and runny nose. In both cases she stopped giving her children the medication within a few days. "I didn't see that it was necessary because neither had asthma," she said.

"I'm not sure if my baby boy had the same experience, but he was never a good sleeper and would scream at night, too. So it's difficult to tell."

Yin saidshe talked to other parents about the drug and got the impression that the "frog medicine" " a reference parents make to Singulair as its packaging features a frog " is commonly prescribed.

Singulair is known as 'frog medicine' in Hong Kong.

Asthma, a condition that affects the airways " the small tubes that carry air in and out of the lungs " is one of the most common chronic diseases, affecting about 300 million people globally.

According to the Hong Kong Asthma Society, about 10 per cent of children and 5 per cent of adults have experienced symptoms of asthma. That means there are about 300,000 to 400,000 asthmatics in the city.

A non-infectious condition, asthma is related to genetic factors and the environment. Common triggers include pollution, smoking, stress, pollen and dust mites.

In the published Gina (Global Initiative for Asthma) guidelines, Singulair is a recommended add-on therapy to inhaled corticosteroid therapy for those suffering moderate to severe asthma. These individuals have daily symptoms of wheezing, are woken from sleep at least three to four times a month from asthma, and have only 60 to 80 per cent or less of their normal lung function.

Lee says this severe group comprises about 10 per cent of asthma patients, but consumes 90 per cent of health care resources targeting asthmatics.

In Hong Kong, there are 52 registered pharmaceutical products containing montelukast, all prescription-only medicines. So far, the Hong Kong Department of Health has received only three reports of adverse drug reaction related to montelukast, one of which related to neuropsychiatric reactions, including speech disorder (strange speech).

My son started seeing things when he was put on this " it was the most real 'daymare' you could imagine: he was on a swing and was convinced snakes were coming out of the nearby bushesA mother describes the side effects her son suffered after taking Singulair

When reports of this month's FDA warning circulated online, Hong Kong Moms Facebook page was inundated with comments. "In 2013, my then four-year-old was on this for two weeks for allergic cough (pre-asthma), and she started getting nightmares. Our paediatrician insisted she continue taking it and 'push through' the side effects. We stopped this drug immediately and changed paediatrician," wrote one.

"My son started seeing things when he was put on this " it was the most real 'daymare' you could imagine: he was on a swing and was convinced snakes were coming out of the nearby bushes. He was petrified. I've refused to give it to any of my kids since, as it was the only medicine he was on!" posted another.

Others were more sanguine. "My son's been on this for two years and it significantly decreased his asthma attacks (from going to hospital every second week, to almost never again). Our GP closely monitored his behaviour after taking the drug and warned us of the side effects," wrote another.

"He just turned five and is the … happiest and most confident kid. Sleeps through the night 12 hours straight. Can do all the sports he loves now because of Singulair. It's important to know there are side effects with all drugs and to not disregard what a medical professional recommends. There are always two sides of the story."

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