Montelukast's Side Effects
For Parents
For Health Care Providers
Links and Resources



Adverse Event Reports are used by the FDA to identify and evaluate safety issues with medications.

Consumers, parents, and health care providers should continue to report ALL side effects from montelukast, including those already acknowledged by the FDA. They must be made aware of how many people have had problems with this drug. 

If your child no longer takes montelukast but continues to experience any of the problems he or she developed while taking it, it is VERY IMPORTANT to file a report about the continuing problem(s).

The Patient and Prescribing Information for this drug has been updated multiple times with additional side effects since the drug was originally approved, in part due to Adverse Reaction Reports from the public.


Montelukast is a leukotriene inhibitor approved by the United States Food and Drug Administration for the treatment of:

- Asthma in adults and children 12 months of age and older
- Exercise-Induced Bronchoconstriction (EIB) in patients 6 years of age and older
- Seasonal Allergic Rhinitis in patients 2 years of age and older
- Perennial (year-round) allergic rhinitis in patients 6 months of age and older

Montelukast is associated with potentially serious neuropsychiatric and physical side effects.

It is marketed worldwide under various names, with the active ingredient listed as Montelukast or Montelukast Sodium.



In March 2015, the FDA issued a reminder to health professionals about the risk of neuropsychiatric events with leukotriene inhibitors, Montelukast (Singulair), Zafirlukast (Accolate), Zileuton (Zyflo, Zyflo CR). Read it here.


In September 2014, the 13 member Pediatric Advisory Committee to the US Food and Drug Administration called for clarifications on labels and for a new letter to providers about Singulair's neuropsychiatric side effects.

"The public testimony phase of the meeting heard from Jan Gilpin, a member of the group Parents United for Pharmaceutical Safety and Accountability, formed in 2009 over concerns that children had developed mental and development issues while on montelukast."



These warnings apply to all products with montelukast as the active ingredient

"Neuropsychiatric events have been reported in adult, adolescent, and pediatric patients taking montelukast sodium. Post-marketing reports with montelukast sodium use include agitation, aggressive behavior or hostility, anxiousness, depression, disorientation, disturbance in attention, dream abnormalities, dysphemia (stuttering), hallucinations, insomnia, irritability, memory impairment, obsessive-compulsive symptoms, restlessness, somnambulism, suicidal thinking and behavior (including suicide), tic, and tremor. The clinical details of some post-marketing reports involving Montelukast sodium appear consistent with a drug-induced effect.

Patients and prescribers should be alert for neuropsychiatric events. Patients should be instructed to notify their prescriber if these changes occur. Prescribers should carefully evaluate the risks and benefits of continuing treatment with Montelukast sodium if such events occur." 


"Patients with asthma on therapy with montelukast sodium may present with systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, a condition which is often treated with systemic corticosteroid therapy. These events have been sometimes associated with the reduction of oral corticosteroid therapy. Physicians should be alert to eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy presenting in their patients. A causal association between montelukast sodium and these underlying conditions has not been established."

This information is current as of December 2018. Check dailymed for the most up to date information.



* Montelukast has NOT been proven the safest and most effective drug to treat asthma or allergies: 

The National Asthma Education and Prevention Program (NAEPP)
recommends that for all age groups, inhaled corticosteroids are the most effective medication for long-term control. Leukotriene receptor antagonists (including Singulair) are considered adjunct (additional) therapy with inhaled corticosteroids, and omalizumab for severe asthma.* (Inhaled corticosteroids are not side effect free.)

Diagnosis and management of rhinitis: An updated practice parameter
Intranasal corticosteroids have been clinically proven the most effective treatment for allergic rhinitis. Adverse reactions usually are limited to the nasal mucosa, with rare systemic effects.***

* Montelukast is not effective for everyone. Clinical research has determined that differential response is due in part to genetic variability.

• The 10mg strength is not approved for use in children under 15.

* Neither risk factors for, nor the actual incidence of, adverse reactions to montelukast is known. After a medication is approved and enters the market, adverse reactions that may not have been reported in clinical trials are identified through voluntary reports to pharmaceutical companies and the FDA's 
MedWatch program. Pharmaceutical companies are required to notify the FDA when they receive adverse event reports, but physicians are not required to report their patients' adverse  reactions. Only those adverse reactions that are reported are considered when re-evaluating the risk/benefit ratio of a medication.

* There is no regulated system to immediately communicate all updated medication information to consumers, physicians, and pharmacists. Healthcare Providers may not be aware of Singulair's updated side effects.

* Consumers and healthcare providers can sign up for
FDA MedWatch e-mail updates to receive updated information about medications/medical products.

* The content of medication information leaflets voluntarily provided by pharmacies is NOT approved by the FDA and may not contain the most up to date information.

* A reliable source of accurate medication information is the
National Library of Medicine's DailyMed website, a database that includes FDA approved labels for prescription drugs. For the most current side effect information, visit the website of the medication manufacturer and read the patient and prescribing information.


PLEASE help raise awareness of montelukast's side effects so that children (and adults) will not continue to suffer needlessly.

REPORT an ADVERSE REACTION (to any medication) to FDA MedWatchREPORT a MEDICATION ERROR to Consumermedsafety.org

SIGN UP for FDA MedWatch e-mail updates, concise, timely information about drugs and medical devices directly from the FDA.

ASK your healthcare provider to check medication information on 


*The EPR 3 Guidelines on Asthma were developed by an expert panel commissioned by the National Asthma Education and Prevention Program (NAEPP) Coordinating Committee (CC), coordinated by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.

**Developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma and Immunology; and the Joint Council of Allergy, Asthma and Immunology, published in the Journal of Allergy and Clinical Immunology, August 2008.


Disclaimer: Parents United for Pharmaceutical Safety and Accountability is a volunteer patient advocacy group. Consult a licensed health care professional before making any medical decisions. Do not stop administering an asthmatic child's medications without the supervision of the child's healthcare provider. The information on this site is intended for educational purposes and should not be construed as medical advice. It is accurate to the best of our knowledge. If you discover an inconsistency, please bring it to our attention.