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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Leukotriene Receptor Antagonist [EPC]
Montelukast is a potent leukotriene receptor antagonist used for the chronic treatment of asthma, the prevention of exercise-induced bronchoconstriction, and the management of seasonal and perennial allergic rhinitis in adults and pediatric patients.
Name
Montelukast
Raw Name
MONTELUKAST SODIUM
Category
Leukotriene Receptor Antagonist [EPC]
Salt Form
Sodium
Drug Count
4
Variant Count
90
Last Verified
February 17, 2026
RxCUI
200224, 242438, 311759, 351246, 153892, 153893, 261367, 404406
UNII
U1O3J18SFL, MHM278SD3E
About Montelukast
Montelukast is a potent leukotriene receptor antagonist used for the chronic treatment of asthma, the prevention of exercise-induced bronchoconstriction, and the management of seasonal and perennial allergic rhinitis in adults and pediatric patients.
Detailed information about Montelukast
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Montelukast.
Montelukast (as Montelukast Sodium) is a selective and orally active leukotriene receptor antagonist (LTRA) that specifically inhibits the cysteinyl leukotriene CysLT1 receptor. It belongs to a pharmacological class of drugs known as leukotriene modifiers. Unlike rescue medications such as albuterol, Montelukast is a maintenance medication designed for long-term control of respiratory inflammation. It was first approved by the U.S. Food and Drug Administration (FDA) in 1998 under the brand name Singulair and has since become a cornerstone in the management of chronic asthma and allergic conditions.
In the context of respiratory health, Montelukast serves a unique role. While inhaled corticosteroids (ICS) are often the first line of defense for asthma, Montelukast provides an alternative or adjunctive systemic therapy that targets a different part of the inflammatory cascade. It is particularly valued for its once-daily oral administration, which can significantly improve patient adherence compared to complex inhaler regimens. Healthcare providers typically prescribe Montelukast for the prophylaxis (prevention) and chronic treatment of asthma in adults and pediatric patients 12 months of age and older, the prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older, and the relief of symptoms of seasonal allergic rhinitis in patients 2 years of age and older.
To understand how Montelukast works, one must understand the role of cysteinyl leukotrienes (LTC4, LTD4, LTE4) in the human body. These are potent inflammatory eicosanoids (signaling molecules) released from various cells, including mast cells and eosinophils. These leukotrienes bind to cysteinyl leukotriene (CysLT) receptors found in the human airway. The binding of leukotrienes to these receptors triggers a series of physiological responses that are detrimental to patients with asthma or allergies: it causes airway edema (swelling), smooth muscle contraction (bronchoconstriction), and altered cellular activity associated with the inflammatory process. In patients with allergic rhinitis, cysteinyl leukotrienes are released from the nasal mucosa after allergen exposure and contribute to symptoms like nasal congestion and sneezing.
Montelukast acts as a high-affinity antagonist. It binds to the CysLT1 receptor with high selectivity, effectively blocking the binding of LTD4 and other leukotrienes. By 'occupying' the receptor, Montelukast prevents the leukotrienes from exerting their inflammatory effects. This results in the inhibition of bronchoconstriction and a reduction in the overall inflammatory response within the lungs and nasal passages. It is important to note that Montelukast does not have any direct bronchodilatory effect like beta-agonists; rather, it prevents the constriction from occurring in the first place. This is why healthcare providers emphasize that it cannot be used to treat an acute asthma attack.
Montelukast is rapidly absorbed following oral administration. For the 10 mg film-coated tablet, the mean peak plasma concentration (Cmax) is achieved approximately 3 hours (Tmax) after administration in adults in a fasted state. The mean oral bioavailability is approximately 64%. Interestingly, the bioavailability and Cmax of the 10 mg tablet are not significantly affected by a standard meal, meaning it can be taken with or without food. For the 5 mg chewable tablet, the mean Cmax is achieved 2 hours after administration in adults in a fasted state, with a bioavailability of 73%.
Montelukast is more than 99% bound to plasma proteins. Its steady-state volume of distribution averages 8 to 11 liters. Studies in rats indicate that Montelukast crosses the blood-brain barrier minimally, although recent clinical data regarding neuropsychiatric effects have led to increased scrutiny of its central nervous system (CNS) penetration in humans.
Montelukast is extensively metabolized in the liver. In studies using human liver microsomes, the cytochrome P450 (CYP) enzymes 3A4, 2C8, and 2C9 were found to be involved in the metabolism of Montelukast. Therapeutic plasma concentrations of Montelukast do not inhibit these enzymes in vivo. The metabolites are generally considered to be inactive or possess very low activity at the CysLT1 receptor.
The plasma clearance of Montelukast averages 45 mL/min in healthy adults. Following an oral dose of radiolabeled Montelukast, 86% of the radioactivity was recovered in 5-day fecal collections and less than 0.2% was recovered in urine. This indicates that Montelukast and its metabolites are excreted almost exclusively via the bile. The mean plasma half-life of Montelukast ranges from 2.7 to 5.5 hours in healthy young adults.
Montelukast is FDA-approved for several distinct indications:
Montelukast is available in several formulations to accommodate different age groups:
> Important: Only your healthcare provider can determine if Montelukast is right for your specific condition. It is not a rescue medication and should not be used to treat sudden shortness of breath.
For the treatment of Asthma or Allergic Rhinitis in adults and adolescents aged 15 years and older, the standard dose is one 10 mg tablet taken once daily.
Pediatric dosing is strictly age-dependent to ensure safety and efficacy:
Because Montelukast and its metabolites are not excreted in the urine, no dosage adjustment is required for patients with renal insufficiency or those on dialysis.
No dosage adjustment is required for patients with mild-to-moderate hepatic insufficiency (Child-Pugh score 7 to 9). The pharmacokinetics of Montelukast in patients with severe hepatic impairment have not been evaluated, so caution is advised in this population.
Clinical studies have shown no significant differences in the safety or effectiveness of Montelukast between elderly and younger patients; therefore, no age-related dosage adjustment is generally necessary.
Montelukast can be taken with or without food.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular dosing schedule. Do not take two doses at once to make up for a missed one. Consistency is key for the long-term management of asthma.
In the event of an overdose, contact a poison control center or seek emergency medical attention immediately. Symptoms of Montelukast overdose may include abdominal pain, somnolence (sleepiness), thirst, headache, vomiting, and psychomotor hyperactivity. There is no specific antidote for Montelukast overdose; treatment is supportive and symptomatic.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, even if you feel better.
Montelukast is generally well-tolerated, but some patients may experience mild side effects. The most frequently reported side effect is headache, occurring in approximately 18% of patients in clinical trials. Other common reactions include:
These effects may occur but are seen less frequently:
Rare but documented side effects include:
> Warning: Stop taking Montelukast and call your doctor immediately if you experience any of the following serious symptoms:
For most patients, long-term use of Montelukast does not lead to cumulative toxicity. However, the risk of neuropsychiatric events remains a constant consideration throughout the duration of therapy. Patients and caregivers should be vigilant for changes in mood or behavior that may develop months or even years into treatment. There is no evidence that Montelukast causes long-term organ damage when used as directed, provided liver function remains normal.
In 2020, the FDA issued a Boxed Warning for Montelukast, the agency's most serious safety warning. This was prompted by an increase in reports of serious neuropsychiatric events.
Summary of FDA Boxed Warning:
Report any unusual symptoms to your healthcare provider promptly.
Montelukast is a maintenance medication. It is critical for patients to understand that it will not stop an acute asthma attack. Patients must always have a rescue inhaler (such as albuterol) available for sudden breathing difficulties. If asthma symptoms worsen or if the rescue inhaler becomes less effective, patients must seek medical attention immediately.
Serious Neuropsychiatric Events: The FDA Boxed Warning (2020) highlights that Montelukast is associated with a risk of serious mental health side effects. These include suicidal thoughts, suicide attempts, and completed suicides. Other reported events include agitation, aggression, depression, sleepwalking, and tremors. Healthcare providers are advised to reserve Montelukast for patients with allergic rhinitis who have an inadequate response or intolerance to alternative therapies. For asthma, providers must weigh the risk of neuropsychiatric events against the benefits of treatment.
Patients with a known hypersensitivity to Montelukast or any of its components should not take the medication. Rare cases of anaphylaxis and angioedema (severe swelling) have been reported.
In rare instances, patients on Montelukast may develop systemic eosinophilia, which can manifest as Churg-Strauss syndrome (a type of blood vessel inflammation). This is most common in patients whose oral corticosteroid dose is being tapered. Symptoms include 'flu-like' illness, rash, pins and needles in arms or legs, and severe sinus pain.
Patients with known aspirin sensitivity should continue to avoid aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) while taking Montelukast. While Montelukast improves airway function in these patients, it does not eliminate the bronchoconstrictor response to aspirin.
There are no specific routine laboratory tests (like blood counts) required solely for Montelukast use. However, healthcare providers should monitor the patient's clinical status closely, particularly regarding:
Montelukast is generally not expected to affect the ability to drive or operate machinery. However, individual responses vary. Some patients have reported dizziness or drowsiness. Patients should determine how they react to the medication before engaging in activities requiring mental alertness.
There is no known direct interaction between Montelukast and alcohol. However, since both can be processed by the liver and alcohol can sometimes worsen asthma or allergy symptoms in certain individuals, moderation is advised. Consult your doctor about your specific alcohol consumption habits.
Montelukast does not typically require a tapering period and can usually be stopped abruptly without a withdrawal syndrome. However, stopping the medication may result in the return of asthma or allergy symptoms. Always discuss discontinuation with your healthcare provider to ensure an alternative management plan is in place.
> Important: Discuss all your medical conditions, especially any history of mental health disorders, with your healthcare provider before starting Montelukast.
While there are no absolute 'never-use' contraindications for Montelukast based solely on drug-drug interactions, certain combinations are highly discouraged due to the risk of significantly altered drug levels.
Montelukast is not known to interfere with most common laboratory tests. It does not affect the results of standard blood chemistry, hematology, or urinalysis. It also does not appear to interfere with skin testing for allergies, unlike antihistamines which must be stopped several days prior to testing.
Most interactions with Montelukast occur via the Cytochrome P450 system, specifically the CYP2C8 and CYP3A4 pathways. Inhibitors of these enzymes (like Gemfibrozil) increase drug levels by slowing down its breakdown, while inducers (like Rifampin) decrease drug levels by speeding up its breakdown.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter allergy or cold medicines.
There is only one primary absolute contraindication for the use of Montelukast:
These are conditions where the use of Montelukast requires a careful risk-benefit analysis by a healthcare professional:
There is no documented cross-sensitivity between Montelukast and other classes of asthma medications, such as inhaled corticosteroids or beta-agonists. However, patients who are sensitive to aspirin should be aware that while Montelukast helps manage their asthma, it does not allow them to safely ingest aspirin or NSAIDs if they have a history of aspirin-induced bronchospasm.
> Important: Your healthcare provider will evaluate your complete medical history, including mental health history and allergies, before prescribing Montelukast.
Montelukast is classified under the older FDA Pregnancy Category B. Available data from published prospective and retrospective cohort studies over decades of use have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. However, poorly controlled asthma during pregnancy increases the risk of adverse outcomes such as preeclampsia, low birth weight, and preterm delivery. Therefore, the decision to use Montelukast during pregnancy should be made in consultation with a healthcare provider, balancing the need for asthma stability against the theoretical risks to the fetus.
Data from limited published literature reports indicate that Montelukast is present in human milk. However, the levels are relatively low. There are no reports of adverse effects on the breastfed infant or on milk production. When considering Montelukast for a nursing mother, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for the medication and any potential adverse effects on the child.
Montelukast is approved for pediatric use in specific age ranges for specific conditions:
Safety and efficacy in infants younger than 6 months have not been established. In pediatric clinical trials, the safety profile was generally similar to that seen in adults, though fever and upper respiratory infections were more common in younger children.
In clinical studies, no overall differences in safety or effectiveness were observed between subjects 65 years of age and older and younger subjects. Elderly patients often have a higher prevalence of comorbid conditions and may be taking multiple medications (polypharmacy), which increases the risk of drug interactions. However, no specific dosage adjustment is required for the elderly based on age alone.
Because Montelukast is primarily excreted through the bile and feces, renal impairment does not significantly affect the drug's pharmacokinetics. No dosage adjustment is recommended for patients with any degree of renal insufficiency, including those requiring hemodialysis.
For patients with mild-to-moderate hepatic insufficiency (Child-Pugh score 7 to 9), no dosage adjustment is necessary. The drug has not been studied in patients with severe hepatic impairment (Child-Pugh score >9). In these patients, the metabolic capacity of the liver is significantly reduced, which could theoretically lead to increased plasma concentrations of Montelukast.
> Important: Special populations require individualized medical assessment. Always inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
Montelukast is a selective cysteinyl leukotriene receptor antagonist with high affinity and selectivity for the CysLT1 receptor. Cysteinyl leukotrienes (LTC4, LTD4, LTE4) are products of arachidonic acid metabolism and are released from various cells, including mast cells and eosinophils. These eicosanoids bind to CysLT receptors. The CysLT1 receptor is found in the human airway (including airway smooth muscle cells and airway macrophages) and on other pro-inflammatory cells. In patients with asthma, leukotriene-mediated effects include bronchoconstriction, mucous secretion, vascular permeability, and eosinophil recruitment. Montelukast inhibits the physiological actions of LTD4 at the CysLT1 receptor without any agonist activity.
Montelukast causes inhibition of bronchoconstriction due to inhaled LTD4. Doses as low as 5 mg cause substantial inhibition of LTD4-induced bronchoconstriction. In clinical trials, Montelukast has been shown to inhibit both the early and late phases of bronchoconstriction due to antigen challenge. It also significantly decreases the number of eosinophils in peripheral blood and airways, which is a marker of improved asthma control.
| Parameter | Value |
|---|---|
| Bioavailability | 64% (10mg tablet) |
| Protein Binding | >99% |
| Half-life | 2.7 to 5.5 hours |
| Tmax | 3 hours (10mg tablet) |
| Metabolism | Hepatic (CYP3A4, 2C8, 2C9) |
| Excretion | Fecal 86%, Renal <0.2% |
Montelukast is classified as a Leukotriene Receptor Antagonist (LTRA). It is part of the broader class of leukotriene modifiers, which also includes 5-lipoxygenase inhibitors like Zileuton. Compared to other LTRAs like Zafirlukast, Montelukast is more commonly prescribed due to its once-daily dosing and lack of significant food-drug interactions for the tablet form.
Medications containing this ingredient
Common questions about Montelukast
Montelukast is primarily used for the long-term prevention and chronic treatment of asthma in adults and children as young as 12 months old. It is also frequently prescribed to prevent breathing difficulties during exercise, a condition known as exercise-induced bronchoconstriction. Additionally, it is highly effective at relieving the symptoms of seasonal and year-round allergies, such as sneezing, stuffy nose, and itchy eyes. It belongs to a class of drugs called leukotriene receptor antagonists, which work by blocking inflammatory chemicals in the body. However, it is important to remember that Montelukast is a maintenance medication and cannot be used to treat an active, sudden asthma attack.
The most common side effect reported by patients taking Montelukast is a headache, which occurs in about 18% of people. Other frequent side effects include symptoms of an upper respiratory infection, such as a sore throat, cough, or nasal congestion. Some patients, particularly children, may experience a fever or abdominal pain shortly after starting the medication. Most of these common side effects are mild and tend to go away as the body becomes accustomed to the drug. However, if any side effect becomes persistent or bothersome, you should consult your healthcare provider. It is also vital to be aware of the more serious, though less common, mental health side effects listed in the FDA's Boxed Warning.
There is no direct, known interaction between Montelukast and alcohol that would make moderate consumption strictly prohibited. However, both alcohol and Montelukast are processed by the liver, so excessive drinking could theoretically increase the strain on your hepatic system. Furthermore, alcohol can sometimes act as a trigger for asthma symptoms or worsen the drowsiness that some people feel while taking allergy medications. If you have a history of liver issues or if you find that alcohol affects your breathing, it is best to limit your intake. Always discuss your lifestyle habits with your doctor to ensure that alcohol consumption is safe for your specific health profile.
Montelukast is generally considered safe for use during pregnancy when the benefits of controlling asthma outweigh the potential risks. Decades of data have not shown a clear link between Montelukast and an increased risk of birth defects or pregnancy complications. It is crucial to maintain well-controlled asthma during pregnancy, as poorly controlled symptoms can lead to serious issues like preeclampsia or low birth weight for the baby. While many doctors continue Montelukast for pregnant patients who were already stable on it, you should always have an explicit conversation with your obstetrician. They will help you weigh the latest clinical evidence against your personal medical needs. Never start or stop the medication during pregnancy without professional guidance.
Most patients begin to see an improvement in their asthma or allergy symptoms within one day of taking the first dose of Montelukast. However, the full therapeutic benefit for chronic conditions may take up to a week or more of consistent daily use to become fully apparent. For the prevention of exercise-induced bronchoconstriction, a single dose should be taken at least two hours before physical activity to be effective. Because it works by blocking the inflammatory cascade rather than instantly relaxing the airways, it requires time to build up its protective effect. It is essential to continue taking the medication every day as prescribed, even if you do not feel an immediate change in your breathing. If your symptoms do not improve after several weeks, contact your healthcare provider.
You can generally stop taking Montelukast suddenly without experiencing physical withdrawal symptoms, as it is not a physically addictive substance. However, stopping the medication will likely cause your asthma or allergy symptoms to return, sometimes quite rapidly. If you are taking Montelukast to manage chronic asthma, stopping it without a replacement therapy could put you at risk for a severe asthma flare-up. You should always consult your healthcare provider before discontinuing the drug to ensure your respiratory health remains stable. They may suggest a different medication or a tapering schedule if they feel it is necessary. Never stop your asthma maintenance medication based on your own judgment, even if you feel completely healthy.
If you miss a dose of Montelukast, you should take it as soon as you remember to maintain consistent levels of the drug in your system. However, if it is almost time for your next scheduled dose, it is better to skip the missed dose entirely and simply take the next one at your usual time. You should never take two doses at once or 'double up' to make up for a missed one, as this could increase the risk of side effects. For asthma patients, the dose is typically taken in the evening, so if you realize the next morning that you forgot, you can take it then or wait until the following evening. Consistency is the most important factor in keeping your airways clear and preventing symptoms. If you find yourself frequently forgetting doses, consider using a pill organizer or a reminder app.
Weight gain is not a commonly reported side effect of Montelukast in clinical trials or post-marketing surveillance. Unlike oral corticosteroids (such as prednisone), which are well-known for causing weight gain and increased appetite, leukotriene receptor antagonists like Montelukast do not typically affect metabolism or fat distribution. If you notice significant or rapid weight gain while taking this medication, it is likely due to another factor, such as a different medication, a change in activity level, or an underlying health condition. Some patients may experience fluid retention in very rare cases, which could cause a slight change in weight. You should discuss any unexpected changes in your weight with your healthcare provider to determine the underlying cause. Overall, Montelukast is considered weight-neutral for the vast majority of patients.
Montelukast can be taken with most other common medications, including inhaled corticosteroids and rescue inhalers, and it is often used as part of a combination therapy for asthma. However, it can interact with certain drugs that affect liver enzymes, such as the seizure medications phenobarbital and phenytoin, or the antibiotic rifampin, which may make Montelukast less effective. It also has a significant interaction with gemfibrozil (a cholesterol medication), which can significantly increase the levels of Montelukast in your blood. You should also be cautious when taking it with other medications that can affect your mood or sleep, due to the risk of neuropsychiatric side effects. Always provide your doctor and pharmacist with a complete list of all prescription drugs, over-the-counter medicines, and supplements you are taking. This allows them to check for potential interactions and ensure your treatment plan is safe.
Yes, Montelukast has been available as a generic medication since the patent for the brand-name drug Singulair expired in 2012. Generic Montelukast is produced by many different pharmaceutical manufacturers and is widely available in all its forms, including the 10 mg film-coated tablets, 4 mg and 5 mg chewable tablets, and the 4 mg oral granules. Generic versions are required by the FDA to have the same active ingredient, strength, dosage form, and route of administration as the brand-name drug. They must also prove bioequivalence, meaning they work in the body the same way as the original. Choosing the generic version can significantly lower your out-of-pocket costs while providing the same therapeutic benefit for your asthma or allergies. Most insurance plans prefer or require the use of the generic form.