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Montelukast and neuropsychiatric reactions

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

A range of neuropsychiatric reactions has been reported in association with montelukast.

  • among these are:
    • sleep disturbances, depression and agitation (may affect up to 1 in 100 people taking montelukast);
    • disturbances of attention or memory (up to 1 in 1,000 people);
    • and very rarely, hallucinations and suicidal behaviour (up to 1 in 10,000 people).

Since first authorised in the UK in 1998, there have been approximately 44 million prescriptions of montelukast issued

  • during this time, the MHRA has received 1,223 reports of suspected neuropsychiatric adverse reactions. Information on neuropsychiatric reactions with montelukast was first introduced in the SmPC in 2008 and a detailed warning was added in 2019
  • of these, the most frequently reported suspected neuropsychiatric reactions associated with montelukast for all age groups were sleep disorders, hallucinations, anxiety and depression, as well as changes in behaviour and mood
  • most frequently reported reactions in younger children (up to and including 12 years old) were aggression, nightmares and anxiety while in older children (13 years old up to and including 17 years old) the most commonly reported were anxiety, suicidal ideation and depression

Advice for healthcare professionals:

  • be alert for neuropsychiatric reactions in patients taking montelukast; events have been reported in adults, adolescents, and children
  • advise patients and their caregivers to read carefully the list of neuropsychiatric reactions in the patient information leaflet and seek medical advice immediately should they occur
  • evaluate carefully the risks and benefits of continuing treatment if neuropsychiatric reactions occur
  • be aware of newly recognised neuropsychiatric reactions of speech impairment (stuttering) and obsessive-compulsive symptoms
  • report suspected adverse drug reactions associated with montelukast to the Yellow Card Scheme


  • Medicines and Healthcare products Regulatory Agency (September 2019). Montelukast (Singulair): reminder of the risk of neuropsychiatric reactions
  • Medicines and Healthcare products Regulatory Agency (April 2024). Montelukast (Singulair): reminder of the risk of neuropsychiatric reactions

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