Does Singulair (montelukast) cause side effects?
Leukotrienes are a group of naturally occurring chemicals in the body that promote inflammation in asthma and seasonal allergic rhinitis and in other diseases in which inflammation is important (such as allergy). They are formed by cells, released, and then bound to other cells that cause inflammation. It is the binding to other cells that stimulates the cells to cause inflammation.
Singulair works in a manner similar to zafirlukast, blocking the binding of some leukotrienes to the cells that cause inflammation. Unlike zafirlukast, Singulair does not inhibit CYP2C9 or CYP3A4, two enzymes in the liver that are important in breaking down and eliminating many drugs.
Therefore, unlike zafirlukast, Singulair is not expected to affect the elimination of other drugs. The safety and effectiveness of montelukast has been demonstrated in children as young as 6 months of age.
Common side effects of Singulair include
- abdominal pain,
- sore throat,
- runny nose,
- tremor, and
Serious side effects of Singulair include
There have been no adequate studies of Singulair in pregnant women to determine the effects on the fetus.
What are the important side effects of Singulair (montelukast)?
The most common side effects with montelukast are:
- abdominal pain,
- sore throat, and
- rhinitis (inflammation of the inner lining of the nose).
Other important side effects include:
Singulair (montelukast) side effects list for healthcare professionals
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.
In the following description of clinical trials experience, adverse reactions are listed regardless of causality assessment.
The most common adverse reactions (incidence ≥5% and greater than placebo; listed in descending order of frequency) in controlled clinical trials were:
- upper respiratory infection,
- abdominal pain,
- otitis media,
Adults And Adolescents 15 Years Of Age And Older With Asthma
Singulair has been evaluated for safety in approximately 2950 adult and adolescent patients 15 years of age and older in clinical trials. In placebo-controlled clinical trials, the following adverse experiences reported with Singulair occurred in greater than or equal to 1% of patients and at an incidence greater than that in patients treated with placebo:
Table 1: Adverse Experiences Occurring in ≥1% of Patients with an Incidence Greater than that in Patients Treated with Placebo
|Body As A Whole|
|Digestive System Disorders|
|Respiratory System Disorders|
|Skin/Skin Appendages Disorder|
|Laboratory Adverse Experiences*|
|* Number of patients tested (Singulair and placebo, respectively): ALT and AST, 1935, 1170; pyuria, 1924, 1159.|
The frequency of less common adverse events was comparable between Singulair and placebo.
The safety profile of Singulair, when administered as a single dose for prevention of EIB in adult and adolescent patients 15 years of age and older, was consistent with the safety profile previously described for Singulair.
Cumulatively, 569 patients were treated with Singulair for at least 6 months, 480 for one year, and 49 for two years in clinical trials. With prolonged treatment, the adverse experience profile did not significantly change.
Pediatric Patients 6 To 14 Years Of Age With Asthma
- Singulair has been evaluated for safety in 476 pediatric patients 6 to 14 years of age.
- Cumulatively, 289 pediatric patients were treated with Singulair for at least 6 months, and 241 for one year or longer in clinical trials.
- The safety profile of Singulair in the 8-week, double-blind, pediatric efficacy trial was generally similar to the adult safety profile.
In pediatric patients 6 to 14 years of age receiving Singulair, the following events occurred with a frequency ≥2% and more frequently than in pediatric patients who received placebo:
- viral infection, and
The frequency of less common adverse events was comparable between Singulair and placebo. With prolonged treatment, the adverse experience profile did not significantly change.
The safety profile of Singulair, when administered as a single dose for prevention of EIB in pediatric patients 6 years of age and older, was consistent with the safety profile previously described for Singulair.
In studies evaluating growth rate, the safety profile in these pediatric patients was consistent with the safety profile previously described for Singulair.
In a 56-week, double-blind study evaluating growth rate in pediatric patients 6 to 8 years of age receiving Singulair, the following events not previously observed with the use of Singulair in this age group occurred with a frequency ≥2% and more frequently than in pediatric patients who received placebo:
- rhinitis (infective),
- atopic dermatitis,
- acute bronchitis,
- tooth infection,
- skin infection, and
Pediatric Patients 2 To 5 Years Of Age With Asthma
Singulair has been evaluated for safety in 573 pediatric patients 2 to 5 years of age in single-and multiple-dose studies. Cumulatively, 426 pediatric patients 2 to 5 years of age were treated with Singulair for at least 3 months, 230 for 6 months or longer, and 63 patients for one year or longer in clinical trials. In pediatric patients 2 to 5 years of age receiving Singulair, the following events occurred with a frequency ≥2% and more frequently than in pediatric patients who received placebo:
- abdominal pain,
- ear pain,
- dermatitis, and
Pediatric Patients 6 To 23 Months Of Age With Asthma
Safety and effectiveness in pediatric patients younger than 12 months of age with asthma have not been established.
Singulair has been evaluated for safety in 175 pediatric patients 6 to 23 months of age. The safety profile of Singulair in a 6-week, double-blind, placebo-controlled clinical study was generally similar to the safety profile in adults and pediatric patients 2 to 14 years of age.
In pediatric patients 6 to 23 months of age receiving Singulair, the following events occurred with a frequency ≥2% and more frequently than in pediatric patients who received placebo:
The frequency of less common adverse events was comparable between Singulair and placebo.
Adults And Adolescents 15 Years Of Age And Older With Seasonal Allergic Rhinitis
Singulair has been evaluated for safety in 2199 adult and adolescent patients 15 years of age and older in clinical trials. Singulair administered once daily in the morning or in the evening had a safety profile similar to that of placebo.
In placebo-controlled clinical trials, the following event was reported with Singulair with a frequency ≥1% and at an incidence greater than placebo: upper respiratory infection, 1.9% of patients receiving Singulair vs. 1.5% of patients receiving placebo. In a 4-week, placebo-controlled clinical study, the safety profile was consistent with that observed in 2-week studies. The incidence of somnolence was similar to that of placebo in all studies.
Pediatric Patients 2 To 14 Years Of Age With Seasonal Allergic Rhinitis
Singulair has been evaluated in 280 pediatric patients 2 to 14 years of age in a 2-week, multicenter, double-blind, placebo-controlled, parallel-group safety study. Singulair administered once daily in the evening had a safety profile similar to that of placebo.
In this study, the following events occurred with a frequency ≥2% and at an incidence greater than placebo:
- otitis media,
- pharyngitis, and
- upper respiratory infection.
Adults And Adolescents 15 Years Of Age And Older With Perennial Allergic Rhinitis
Singulair has been evaluated for safety in 3357 adult and adolescent patients 15 years of age and older with perennial allergic rhinitis of whom 1632 received Singulair in two, 6-week, clinical studies. Singulair administered once daily had a safety profile consistent with that observed in patients with seasonal allergic rhinitis and similar to that of placebo.
In these two studies, the following events were reported with Singulair with a frequency ≥1% and at an incidence greater than placebo:
- upper respiratory infection,
- sinus headache,
- epistaxis, and
- increased ALT.
The incidence of somnolence was similar to that of placebo.
Pediatric Patients 6 Months To 14 Years Of Age With Perennial Allergic Rhinitis
The safety in patients 2 to 14 years of age with perennial allergic rhinitis is supported by the safety in patients 2 to 14 years of age with seasonal allergic rhinitis. The safety in patients 6 to 23 months of age is supported by data from pharmacokinetic and safety and efficacy studies in asthma in this pediatric population and from adult pharmacokinetic studies.
The following adverse reactions have been identified during post-approval use of Singulair. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Blood and lymphatic system disorders: increased bleeding tendency, thrombocytopenia.
Immune system disorders: hypersensitivity reactions including anaphylaxis, hepatic eosinophilic infiltration.
Psychiatric disorders: including, but not limited to, 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.
Nervous system disorders: drowsiness, paraesthesia/hypoesthesia, seizures.
Cardiac disorders: palpitations.
Respiratory, thoracic and mediastinal disorders: epistaxis, pulmonary eosinophilia.
Hepatobiliary disorders: Cases of cholestatic hepatitis, hepatocellular liver-injury, and mixed-pattern liver injury have been reported in patients treated with Singulair. Most of these occurred in combination with other confounding factors, such as use of other medications, or when Singulair was administered to patients who had underlying potential for liver disease such as alcohol use or other forms of hepatitis.
Renal and urinary disorders: enuresis in children.
General disorders and administration site conditions: edema.
Patients with asthma on therapy with Singulair 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.
What drugs interact with Singulair (montelukast)?
No dose adjustment is needed when Singulair is co-administered with
Singulair (montelukast) is an oral leukotriene receptor antagonist used to treat asthma and seasonal allergic rhinitis (hay fever). Common side effects of Singulair include headache, dizziness, abdominal pain, sore throat, runny nose, wheezing, cough, rash, restlessness, tremor, and nausea. There have been no adequate studies of Singulair in pregnant women to determine the effects on the fetus. It is unknown if Singulair is secreted into human breast milk. Consult your doctor before breastfeeding.
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Related Disease Conditions
An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in people who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock.
Asthma: Over the Counter Treatment
Patients who have infrequent, mild bouts of asthma attacks may use over-the-counter (OTC) medications to treat their asthma symptoms. OTC asthma medicines are limited to epinephrine and ephedrine. These OTC drugs are best used with the guidance of a physician, as there may be side effects and the drugs may not be very effective.
Asthma is a condition in which hyperreactive airways constrict and result in symptoms like wheezing, coughing, and shortness of breath. Causes of asthma include genetics, environmental factors, personal history of allergies, and other factors. Asthma is diagnosed by a physician based on a patient's family history and results from lung function tests and other exams. Inhaled corticosteroids (ICS) and long-acting bronchodilators (LABAs) are used in the treatment of asthma. Generally, the prognosis for a patient with asthma is good. Exposure to allergens found on farms may protect against asthma symptoms.
COPD vs. Asthma (Differences and Similarities)
COPD (chronic obstructive pulmonary disease) and asthma both have common symptoms like coughing, wheezing, shortness of breath, and a tight feeling in the chest. COPD is caused by tobacco smoking, while asthma is caused by your inherited genetic makeup and their interactions with the environment. Risk factors for asthma are obesity, exposure to cigarette smoke (even secondhand smoke), and personal history of hay fever. There is no cure for either disease, but symptoms can be managed with medication. A person with asthma has a better prognosis and life expectancy than someone with COPD.
COVID-19 vs. Allergies
Though there is some overlap in allergy and COVID-19 signs and symptoms there are also significant differences. Symptoms that they have in common include headache, fatigue, tiredness, shortness of breath, wheezing, and sore throat. Fever does not occur with allergies but is one of the defining symptoms of COVID-19 infections.
There are two types of asthma medications: long-term control with anti-inflammatory drugs and quick relief from bronchodilators. Asthma medicines may be inhaled using a metered-dose inhaler or nebulizer or they may be taken orally. People with high blood pressure, diabetes, thyroid disease, or heart disease shouldn't take OTC asthma drugs like Primatene Mist and Bronkaid.
Sinus Infection vs. Allergies
Both sinus infections and allergies (allergic rhinitis) cause symptoms such as runny or stuffy nose and fatigue. Sinus infection (known as sinusitis) is inflammation of the sinuses, caused by infection from bacteria, viruses, and/or fungi (molds). Allergic rhinitis occurs when certain allergies cause nasal symptoms. When a person with allergies breathes in an allergen, such as pollen, dust, or animal dander, symptoms such as runny or stuffy nose, itching, sneezing, and fatigue occur.
There are many unusual symptoms of asthma, including sighing, difficulty sleeping, anxiety, chronic cough, recurrent walking pneumonia, and rapid breathing. These symptoms may vary from individual to individual. These asthma complexities make it difficult to accurately diagnose and treat asthma.
Asthma in Children
Asthma in children manifests with symptoms such as coughing and wheezing. Rates of asthma in children are increasing. Asthma in children is usually diagnosed based on the description of symptoms. Lung function tests may also be used. A variety of medications are used for the treatment of childhood asthma.
Occupational asthma is a type of asthma caused by exposure to a substance in the workplace. Symptoms and signs include wheezing, chest tightness, and shortness of breath. The usual treatment for occupational asthma involves removal from exposure and the use of bronchodilators and inhaled anti-inflammatory medicines.
Adult-onset asthma is asthma that is diagnosed in people over 20 years of age. Symptoms include wheezing, coughing, shortness of breath and difficulty breathing. Treatment may involve anti-inflammatory medications or bronchodilators.
What Are the Four Types of Asthma?
Asthma is a chronic inflammatory disease of the airways (bronchi). Bronchi generally allow for the passage of air in and out of the lungs. In asthma, these airways develop hypersensitivity, inflammation, and narrowing. This causes difficulty in breathing. The four types are mild intermittent, mild persistent, moderate persistent and severe persistent.
Exercise-induced asthma is asthma triggered by vigorous exercise. Symptoms include coughing, shortness of breath, chest tightness, wheezing, and fatigue while exercising. Preventing exercise-induced asthma attacks involves using inhaled medicines before exercising, performing warm-up exercises and cooling down afterward, avoiding exercising outdoors when pollen counts are high, restricting exercise when you have a viral infection, and wearing a mask over your nose and mouth when exercising in cold weather.
Can asthma go away?
Asthma is a long-term condition for many people, particularly if it first develops when you're an adult. In children, it sometimes goes away or improves during the teenage years, but can come back later in life.
Treatment & Diagnosis
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Medications & Supplements
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.