Montelukast Side Effects and Safety: What the FDA Record Shows

Montelukast Side Effects are documented on the FDA prescribing label, and reported separately by patients and doctors to the FDA’s adverse event system. This page sets out what the official record actually says about Montelukast: what it is approved to treat, what the label warns about, its recall history, and what the reported side effects are — along with what those figures do and do not mean.

What Montelukast Is Prescribed For, and Where Montelukast Side Effects Come From

According to the FDA label, is a leukotriene receptor antagonist indicated for: Prophylaxis and chronic treatment of asthma in patients 12 months of age and older ( 1.1 ). Acute prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older ( 1.2 ). Relief of symptoms of allergic rhinitis (AR): seasonal allergic rhinitis (SAR) in patients 2 years of age and older, and perennial allergic rhinitis (PAR) in patients 6 months of age and older.

Reserve use for patients who have an inadequate response or intolerance to alternative therapies ( 1.3 ). […]

Two separate official sources describe montelukast side effects. The prescribing label records what was observed in clinical trials, where the drug was compared against a control group. The FDA’s adverse event database records what patients and clinicians have reported since approval, which is a much larger but far less controlled picture. Both appear below, and they answer different questions.

The FDA has revised this label recently. The label’s own record of recent major changes reads: Indications and Usage ( 1.3 , 1.4 ) 02/2021 Dosage and Administration ( 2.1 , 2.2 , 2.3 , 2.4 ) 02/2021 Warnings and Precautions ( 5.1 , 5.6 ) 02/2021 A recent revision usually means new safety information was added.

The FDA Boxed Warning on Montelukast

A boxed warning is the most serious warning the FDA requires on a prescription label. It does not mean the medicine should not be used. It means there is a specific risk serious enough that the FDA requires it to appear at the very top of the prescribing information, so that prescribers weigh it deliberately for each patient.

Prescribers see this warning every time they consult the label. If it concerns you, it is a reasonable thing to raise at your next appointment and ask how it applies to your own situation.

Warnings Beyond the Common Montelukast Side Effects

The label’s warnings and precautions section describes risks the FDA requires prescribers to weigh. For Montelukast it covers: o not prescribe SINGULAIR to treat an acute asthma attack ( 5.2 ). Advise patients to have appropriate rescue medication available ( 5.2 ). Inhaled corticosteroid may be reduced gradually. Do not abruptly substitute SINGULAIR for inhaled or oral corticosteroids ( 5.3 ). Patients with known aspirin sensitivity should continue to avoid aspirin or non-steroidal anti-inflammatory agents while taking SINGULAIR ( 5.4 ).

Systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, has been reported. These events have been sometimes associated with the reduction of oral corticosteroid therapy ( 5.5 and 6.2 ). Inform patients with phenylketonuria that the 4-mg and 5-mg chewable tablets contain phenylalanine ( 5.6 ). 5.1 Neuropsychiatric Events Serious neuropsychiatric (NP) events have been reported with use of SINGULAIR. […]

These are the risks the FDA has judged significant enough to state formally, and they sit apart from the routine montelukast side effects most people ask about. They apply to different patients to very different degrees, which is why the same medicine can be routine for one person and unsuitable for another.

Montelukast Side Effects Listed on the FDA Label

The label’s adverse reactions section records what was observed in clinical trials: he following clinically significant adverse reactions are described elsewhere in the labeling: Neuropsychiatric Events [see Warnings and Precautions (5.1) ] Most common adverse reactions (incidence ≥5% and greater than placebo listed in descending order of frequency): upper respiratory infection, fever, headache, pharyngitis, cough, abdominal pain, diarrhea, otitis media, influenza, rhinorrhea, sinusitis, otitis ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Organon LLC, a subsidiary of Organon & Co., Inc., at 1-844-674-3200 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. […]

Trial data is the most reliable source for how common montelukast side effects are, because the people taking the drug were compared against people who were not. A symptom that appeared just as often in the control group is not caused by the medicine.

Reported Montelukast Side Effects in the FDA Database

Who the Label Says Should Take Extra Care

Contraindications. The label states that Montelukast should not be used in certain situations: is contraindicated in patients with hypersensitivity to any of its components. Hypersensitivity to any component of SINGULAIR ( 4 ).

Interactions with other medicines. o dose adjustment is needed when SINGULAIR is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin, gemfibrozil, itraconazole, thyroid hormones, sedative hypnotics, non-steroidal anti-inflammatory agents, benzodiazepines, decongestants, and Cytochrome P450 (CYP) enzyme inducers [see Clinical Pharmacology (12.3) ].

Older adults. 8.5 Geriatric Use Of the total number of subjects in clinical studies of montelukast, 3.5% were 65 years of age and over, and 0.4% were 75 years of age and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. […]

Your pharmacist can check your full medicine list against this in a couple of minutes, including anything bought over the counter, and that check is free.

Montelukast Recall History

The FDA enforcement database records 6 recall entries involving Montelukast products (1 Class I, 3 Class II, 2 Class III). A recall almost always concerns specific manufactured batches rather than the medicine itself, and different manufacturers of the same generic drug have separate recall records.

The FDA classifies recalls by how serious the potential consequence is. Class I means a reasonable probability of serious harm or death; Class II means temporary or reversible harm is possible; Class III means the product breaks a regulation but is unlikely to cause harm.

If a batch you have was recalled, the pharmacy that dispensed it is the fastest way to find out and to get a replacement. Do not simply stop taking a prescribed medicine because a recall notice exists — the recall may not affect your batch, and stopping can carry its own risk.

Is Montelukast the Subject of Litigation?

As of the date on this page, we are not tracking consolidated federal litigation over Montelukast. Safety questions have been raised about this medicine, and questions being raised is not the same thing as a case being filed or proven.

We monitor federal court filings and FDA safety communications, and this page is updated when the record changes. Our active case pages list the drug and device litigation currently underway.

If You Are Worried About Montelukast Side Effects

Concern about montelukast side effects is a good reason to have a conversation, and not a reason to act alone. Do not stop taking a prescribed medicine, or change how you take it, because of anything you read here. Talk to the prescriber or pharmacist who knows your medical history first. Stopping some medicines abruptly carries risks of its own, and your prescriber can tell you whether that applies to yours.

Write down what you have noticed and when it started before the appointment. Not everything that happens while taking a medicine is one of its montelukast side effects, and a specific account — what changed, when, and how often — is what lets a clinician tell the difference.

You can also report a side effect directly to the FDA through MedWatch. Reports from patients are part of how safety signals are detected, and filing one takes a few minutes.

Frequently Asked Questions

What are the most commonly reported montelukast side effects?

In FDA reports, the most frequently mentioned are dyspnoea, asthma, fatigue. The label’s own adverse reactions section, drawn from clinical trials, is the better guide to how common a side effect actually is, because reports to the FDA are not collected in a way that supports rates.

Has Montelukast been recalled?

There are 6 recall records for Montelukast products, the most recent dated 2023-11-15. Recalls generally affect specific manufactured batches rather than the medicine as a whole. Your pharmacy can tell you whether a batch you have was affected.

Does Montelukast have a boxed warning?

Yes. The boxed warning is reproduced above. It is the most serious warning the FDA requires, and it exists so that prescribers weigh a specific risk for each patient rather than overlooking it.

Do the FDA report numbers tell me how common these montelukast side effects are?

No. Reports are unverified, anyone can file one, and the total mostly reflects how many people take the medicine and how much attention it is getting. A high count is not evidence of danger, and a low one is not evidence of safety. Clinical trial data on the label is the source that supports rates.

Where can I check montelukast side effects for the exact product I have?

DailyMed holds the current FDA label for every marketed product, searchable by the name on your packaging. Different manufacturers and formulations of the same medicine can have slightly different labels, so checking the one you actually have is worth the two minutes.

Official Sources

• DailyMed (National Library of Medicine) — the current FDA prescribing label for every product
• FDA Adverse Event Reporting System dashboard — the public report data summarised above
• FDA recalls and safety alerts — current recall notices
• FDA MedWatch — how to report a side effect yourself

Related Guides

• All Drug Safety Profiles
• Drug Safety Explainers
• Product Recalls
• Active Case Pages

Medical and legal disclaimer. This page summarises publicly available FDA data about Montelukast and is general information, not medical advice, and not legal advice. It is not a substitute for the judgement of a clinician who knows your medical history. Nothing here states that Montelukast caused any illness or injury in any individual. Adverse event reports are unverified and do not establish causation.

FDA labels are revised regularly; confirm current information on DailyMed or with your pharmacist. Do not stop taking a prescribed medicine, or change how you take it, because of anything you read here. Talk to the prescriber or pharmacist who knows your medical history first.