Concerned about asthma drug’s side effects? Ask a doctor.

The messages started appearing in Dr. Ryan Murphy’s inbox this week shortly after a New York Times article renewed concerns about reported side effects of asthma drug montelukast, also known as Singulair. 

Evidence of neuropsychiatric side effects have existed since the drug’s initial approval more than a quarter-century ago. Those concerns are usually front of mind when Murphy considers prescribing it to a patient who is struggling with asthma or allergic sinus disease.

“With every patient, I will tell them, ‘I want you to keep a very close eye out for if you're feeling that you're just not yourself and you feel like you're off,’” Murphy said. “That's a potential risk of being on this medicine.”

Questions about montelukast reemerge with each news event involving the drug. The Food and Drug Administration put a black box warning on the drug in 2020, waving a flag at users and prescribers — but without limiting access to the medication. 

“Do you need to be on this medicine?” Murphy noted that montelukast is not uniformly effective for everyone with asthma, and that other treatment options are available. “If you're getting benefit from it, not having side effects, it seems like that's a good deal. If you're getting some modest benefits but experiencing side effects, what's the cost-benefit analysis there? But if you're not getting benefit at all, regardless of side effects or not, it's not a medicine you should be taking.” 

He emphasized that the overwhelming majority of patients who take montelukast experience no ill effects. It effectively counteracts inflammation in the lungs for many people, particularly those with exercise-related symptoms and those with sinus polyps. 

Nonetheless, concerns have arisen about whether the FDA’s warning has done enough to lower montelukast prescriptions, which numbered 12 million in 2022, according to prescribing data provided to The New York Times by Komodo Health. Of particular concern is the drug’s potential effects on child brain development. More than 1.6 million children were prescribed the drug last year. 

Murphy said he tells patients about potential side effects such as abnormal behavior, anxiety, depression, agitation and insomnia. While prescreening patients is important, he said, doctors also should follow up to ensure patients are benefiting from prescribed montelukast.

For parents whose children take montelukast and who are unfamiliar with the side-effect concerns, Murphy suggests contacting your doctor.

“Just have a close conversation with your primary care doctor or your asthma or allergy specialist about, ‘Does my son or daughter need to be on this medication?’” Murphy said. “And if they do need to be on it, what's the evidence that it's providing true benefit?”

Related: Download broadcast-ready soundbites with Murphy on asthma medications.

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