Neuropsychiatric reactions with the use of montelukast

A 13 year old boy was started on 5 mg montelukast daily in addition to low dose inhaled corticosteroids to treat his asthma. Within a few days, his mother noted that he was constantly arguing and wanted to hit and kick other people. He had not shown this behaviour earlier. At the time of prescribing, their doctor had asked for any history of psychiatric illnesses in their family, which they had none. The doctor had advised her to observe the child and report any changes in behaviour after starting the drug.

Montelukast, used in patients with asthma or allergic rhinitis, is associated with a risk of neuropsychiatric adverse reactions (see box 1). These are uncommon and usually mild but can be worrisome and affect quality of life for patients and their families. Rarely, serious adverse reactions such as depression and suicide have been reported, mostly with prolonged use.8 Neuropsychiatric symptoms may be attributed to normal behavioural changes in children or to other conditions. Failure to recognise these adverse drug reactions early can result in serious harm to patients and their families.