What are the neurological side effects of montelukast?

Neurological side effects reported with montelukast range from mild to serious, with most data coming from post-marketing surveillance and pharmacovigilance databases.

What exactly shows up in adverse-event reports
Tremor, dizziness, and headache appear most often. Less frequent but documented events include sleep disturbances, irritability, anxiety, depression, hallucinations, and seizures. Some reports note paresthesia or memory problems, though causality is harder to establish for these.

How common are these effects in real-world use
In large observational cohorts, neurological complaints occur in roughly 1–3 % of users, with sleep-related issues and mood changes driving most discontinuations. Incidence rises in children and adolescents, prompting label updates in several countries.

Why regulatory agencies added warnings
In 2020 the FDA placed a boxed warning on montelukast after reviewing cases of neuropsychiatric events, including completed suicides. European and Canadian agencies followed with similar precautions, emphasizing that risk may be higher in patients with prior psychiatric history.

What happens when patients stop the drug
Most neuropsychiatric symptoms resolve within days to weeks after discontinuation, though a minority report lingering mood or sleep changes. No specific tapering schedule is recommended; abrupt cessation is standard.

Who should avoid or use extra caution
Guidelines advise against first-line use in patients with active depression, bipolar disorder, or prior suicide attempts. When montelukast is still chosen, clinicians are urged to discuss symptoms proactively at each visit and to document baseline mood and sleep status.

Are there safer alternatives for the same indications
Inhaled corticosteroids remain preferred for persistent asthma; intranasal steroids or antihistamines for allergic rhinitis. When montelukast is required, short courses or intermittent use may reduce cumulative exposure.

What ongoing studies or litigation look like
Several class-action suits in the US and Canada allege failure to warn earlier. Ongoing pharmaco-epidemiologic analyses using large claims databases are examining whether montelukast exposure correlates with incident psychiatric diagnoses in pediatric populations.