Montril

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Montril

Quick Facts

Property Description
Active ingredient Montelukast (as Montelukast sodium)
Form Tablets, chewable tablets, and oral granules
Pharmacological class Cysteinyl Leukotriene Receptor Antagonist (CysLTRA)
Common use Maintenance treatment for chronic respiratory issues
Origin Synthetic, non-steroidal compound
Status Prescription Drug (Rx)

What is Montril and What is its Active Ingredient?

Montril is a synthetic, non-steroidal medication designated as a Prescription Drug (Rx) and a single-ingredient product, containing Montelukast (formulated as Montelukast sodium) as its sole active component. It is exclusively intended for oral administration (ingestion). The drug is offered in several physical oral dosage forms, including standard tablets, chewable tablets, and oral granules. The availability of the chewable and granule forms makes it particularly versatile for pediatric patients, a key differentiating factor in the overall clinical use of montelukast.

Montril's Pharmacological Class and General Purpose

Montril belongs to the highly specific pharmacological class known as Cysteinyl Leukotriene Receptor Antagonists (CysLTRAs). This classification dictates that its general purpose is to act as an Anti-asthmatic agent for maintenance treatment and prophylaxis of certain chronic respiratory conditions. Its mechanism involves antagonism—specifically, blocking the action of inflammatory messengers called leukotrienes.

CysLTRAs function as agents that interfere with the underlying inflammatory process in the airways, serving a key role in managing chronic symptoms. Therefore, the primary benefit of Montril is stabilizing pulmonary function by ensuring sustained airway openness and managing the chronic inflammation associated with respiratory conditions.

Regulatory References

  1. NIH StatPearls
  2. NIH: Asthma - StatPearls

What side effects are possible with Montril?

Possible Side Effects and Safety Information

The safety profile of Montril (montelukast) is defined by officially documented adverse reactions organized by frequency and physiological system. This information is derived from government regulatory documents, such as the FDA and EMA prescribing information.


Frequency-Classified Adverse Reactions

The official label classifies adverse reactions based on how often they have been reported:

  • Common (occurring in 1 in 100 to less than 1 in 10 patients): Headache and abdominal pain.
  • Uncommon (occurring in 1 in 1,000 to less than 1 in 100 patients): Reactions such as hypersensitivity, agitation, abnormal dreams, sleep disorders, and dizziness are documented in this category.

System-Organ-Class Safety Summary

Adverse effects are mapped to specific organ systems, including Psychiatric disorders, Nervous system disorders, Gastrointestinal disorders, and Hepatobiliary disorders.


Serious Adverse Reactions and Restrictions

The most significant safety characteristic noted in regulatory warnings relates to Neuropsychiatric Events. These serious, though less frequent, adverse reactions include mood and behavior changes, such as anxiety, depression, and suicidal thoughts and behavior.

Less common but serious systemic events, such as Eosinophilia and Systemic Vasculitis (Churg-Strauss Syndrome), are also reported in the regulatory profile. Montril is not indicated for the reversal of acute respiratory events like bronchospasm.


Population-Specific Notes

The chewable tablet formulation contains a source of phenylalanine and is therefore a specific constraint for individuals with Phenylketonuria (PKU). The safety profile also includes distinct considerations for pediatric patients.

Overdose and Emergency Response

The official regulatory documentation for Montelukast (Montril) details the expected clinical presentations and mandated emergency actions in the event of an overdose. Documented acute manifestations reported in high-dose exposures include central nervous system effects such as drowsiness, agitation, and restlessness, alongside gastrointestinal issues like vomiting, nausea, and stomach pain. Other symptoms noted in official reports are headache and thirst.

In any case of suspected overdose, regulators mandate that immediate medical attention must be sought, and the Poison Help line should be contacted for guidance. Furthermore, the observation of severe or life-threatening clinical triggers, such as seizure or indications of suicidal thinking and behavior, requires an immediate call to emergency services.

The standard procedural approach for managing Montril overdose is strictly symptomatic and supportive treatment, as regulatory authorities state that no specific antidote is known. Overdose review also includes cases involving pediatric patients (5 years old and younger), where the reported signs were consistent with the general documented profile.

Therapeutic Uses of Montril

What Montril Treats: Main Uses and Benefits

Montril (montelukast) is primarily applied across domains where additional symptomatic support is needed, specifically addressing respiratory and allergic conditions. The medication is considered relevant for easing symptoms across three main therapeutic areas.

It is used in situations involving certain distressing symptoms across three main contexts: long-term management of chronic asthma symptoms, the prevention of exercise-induced bronchoconstriction (EIB), and relief from allergic rhinitis manifestations.


Asthma and Allergy Symptom Support

Montril is commonly used across conditions characterized by periods of heightened symptoms, helping to address symptom clusters that may become intense or disruptive. The medication provides support that helps ease the overall symptom burden associated with chronic airway discomfort and allergic reactions.

Quick Fact: Supports management of symptoms related to Nasal Congestion

It is applied when supportive symptom management is appropriate to improve day-to-day comfort and supports patients during episodes of heightened discomfort.

Eligibility and Restrictions for Use

Who Can and Cannot Use Montril?

Eligibility to use Montril (montelukast) is determined by specific population criteria and patient-specific conditions as documented in official regulatory labeling.


Absolute Contraindications

Montril must not be used if a patient has a known hypersensitivity to Montelukast or any component of the product. The medication is also not indicated for use in reversing acute asthma attacks.

Age-Related Eligibility

Condition Minimum Approved Age Use Status Below Minimum Age
Chronic Asthma 12 months Safety and effectiveness not established
Perennial Allergic Rhinitis (PAR) 6 months Safety and effectiveness not established
Exercise-Induced Bronchoconstriction (EIB) 6 years Safety and effectiveness not established

Use in Vulnerable Populations

  • Pregnancy and Lactation: Use during pregnancy or breastfeeding is permitted only if clearly needed, as Montelukast is excreted in human milk.
  • Hepatic Impairment: No dosage adjustment is necessary for mild to moderate liver impairment; however, use in severe hepatic impairment has not been evaluated by regulatory agencies.
  • Older Adults: No specific dosage adjustment is required, although clinical trials did not include sufficient data on patients 65 years and over.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documents detail the known pharmacokinetic interactions of Montril (Montelukast), primarily involving the cytochrome P450 enzyme system, which is responsible for the drug’s metabolism. The product is not anticipated to significantly alter the metabolism of other medications.

Interacting Medicinal Products and Pharmacokinetic Effects:

Interaction Partner(s) Official Documented Effect Constraint/Context
Phenobarbital Decreases Montelukast exposure by approximately 40% (via CYP3A4 induction) Strong CYP Enzyme Inducers may reduce the effectiveness of Montelukast. Appropriate clinical monitoring is recommended.
Gemfibrozil Increases Montelukast systemic exposure by 4.4-fold (via CYP2C8/2C9 inhibition) No routine dose adjustment is required, but physicians should be aware of the potential for increased systemic exposure.
Rifampin Potent inducer of CYP enzymes (CYP3A4, 2C8, and 2C9) Use with caution, especially in children, due to potential for reduced Montelukast exposure.

Products Without Clinically Significant Interaction:

Interaction studies have shown that the recommended clinical dose of Montelukast did not have clinically important effects on the pharmacokinetics of several commonly used medications. These agents include Theophylline, Prednisone, Prednisolone, Warfarin, Digoxin, and Oral Contraceptives (Ethinyl Estradiol/Norethindrone). Montelukast is not anticipated to markedly alter the metabolism of drugs metabolized by CYP2C8. There are no explicitly stated timing-based restrictions for administration.


This interaction profile is structured around the potential for other medications to reduce the exposure of Montelukast, primarily through hepatic enzyme induction. Conversely, Montelukast itself demonstrates a low potential to alter the concentrations of most co-administered drugs.

Mechanism of Action

How Montril Works

Montril's action is a focused blockade of a specific inflammatory signaling pathway.

Specific Blockade of the CysLT1 Receptor

Montelukast, the active ingredient, functions as a specific competitive antagonist by binding with high affinity to the Cysteinyl Leukotriene Receptor Type 1 (CysLT1). This mechanism directly blocks the inflammatory mediators ( LTD4, LTC4, LTE4) from the 5-Lipoxygenase pathway from activating the receptor, thereby suppressing the initiation of their cellular cascade.

Modulation of Airway Smooth Muscle and Edema

The receptor blockade halts the signal that would normally cause the smooth muscles in the bronchial tubes to contract, effectively preventing cysLT-mediated bronchial smooth muscle contraction. Concurrently, this mechanism dampens the leukotriene-mediated increase in vascular permeability and the recruitment of inflammatory cells, collectively reducing the physiological phenomena of airway tissue edema and inflammatory cell infiltration.

Causal Chain to Physiological Stability

By inhibiting the molecular events that drive bronchial smooth muscle contraction and cysLT-mediated tissue changes, Montelukast engages a mechanism that contributes to limiting the influence of cysLTs on respiratory tract tissue. The resulting physiological effect is the prevention of cysLT-mediated narrowing of the bronchial lumen, which is a consequence of inhibiting this specific inflammatory pathway.

Dosage and Administration Information

How to Use Montril

Montril (montelukast) is strictly intended for oral administration across all available forms, including film-coated tablets, chewable tablets, and oral granules. The specific formulation and strength prescribed are determined by the patient's age and clinical context.


Standard Dosage and Frequency

For the maintenance treatment of chronic conditions, Montril is administered once daily. The dose should be taken in the evening for managing asthma and concomitant conditions. Dosing is structured around age group, not weight, to maintain appropriate plasma concentrations:

Patient Age Group Daily Maintenance Dose Formulation
Adults ≥ 15 years 10 mg Film-coated tablet
Children 6-14 years 5 mg Chewable tablet
Children 6 months to 5 years 4 mg Chewable tablet or Oral Granules

Montril is intended for chronic, continuous use for maintenance treatment, and administration should not be interrupted even during periods when symptoms are controlled.


Administration Conditions and Special Uses

The medication may be taken with or without food. For the prevention of Exercise-Induced Bronchoconstriction (EIB), a single 10 mg dose is administered at least 2 hours prior to exercise; this dose must not be taken within 24 hours of a previous dose.

Oral granules may be administered directly into the mouth or mixed with a spoonful of cold or room temperature soft food (such as applesauce). If mixed, the full dose must be administered immediately, within 15 minutes, of opening the packet. No dosage adjustment is required for older adults or patients with mild-to-moderate hepatic or renal impairment.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Montril

Evidence from Studies on Chronic Asthma Management

Research has studied Montril in trials focusing on conditions where symptoms may vary in intensity. Studies monitored people with persistent asthma, focusing on outcomes reflecting daily functioning or activity level over defined time intervals. Findings describe patterns measured in functional lung measures, such as objective measurements of breathing ability. Studies monitored changes in symptom intensity or variability. Evidence quality varies across studies, and comparative research against alternative established therapies has been conducted. Results apply primarily only to the specific populations and conditions studied.


Evidence from Studies on Exercise-Induced Bronchoconstriction (EIB)

Research explored Montril in studies examining short-term symptom changes related to episodic or acute changes. Specific studies monitored individuals facing conditions associated with acute or disruptive episodes, such as exercise. The research monitored breathing function parameters during temporary exercise challenges. Studies report patterns observed in the monitored populations related to changes in breathing function immediately following exercise. The duration of the observed changes in breathing function following exercise may vary, and research does not determine whether an individual will observe similar patterns.


Evidence from Studies on Allergic Rhinitis

Research explored Montril in studies focusing on outcomes linked to inflammatory or irritative states, such as allergic rhinitis. Studies explored how outcomes related to physical discomfort, like nasal blockage and sneezing, changed over time. Findings indicate that measurements of symptoms related to daily functioning were reported during the study period. Subgroup findings are uncertain, especially concerning the study patterns in conditions characterized by fluctuating or episodic manifestations.


What Research Gaps and Uncertainties Exist

Evidence quality varies across studies, and comparative evidence against a full range of alternative established therapies is limited in some areas. Sample sizes were modest in some specific trials, and results apply only to the populations studied. The main consistent theme is that long-term outcomes related to symptom control are not fully established, and data are still emerging regarding certain clinical scenarios. Findings were mixed in some studies, and research provides context but not individual predictions about whether an individual will experience similar outcomes.

Key Studies & References

  1. Efficacy of Montelukast in Allergic Rhinitis Treatment: A Systematic Review and Meta-Analysis

Frequently Asked Questions (FAQ)

Common questions about Montril (FAQ)


Q: How does Montril compare generally to similar over-the-counter products?

Montril is categorized as a prescription-only drug, known as a leukotriene receptor antagonist (LTRA). This means it requires a prescription and works by blocking specific inflammatory messengers in the body. Over-the-counter (OTC) products used for related symptoms, such as basic decongestants, belong to different drug classes and operate through different mechanisms than Montril.


Q: Is Montril a type of antibiotic?

No, Montril is not an antibiotic. It is a non-steroidal anti-asthmatic agent classified as a Cysteinyl Leukotriene Receptor Antagonist (CysLTRA). Its purpose is to help block inflammatory mediators in the airways and is not intended to treat bacterial infections.


Q: Does Montril affect blood pressure?

Official information from clinical studies indicates that Montril was not reported to cause an increase in blood pressure. The drug is not a steroid, which are sometimes associated with such cardiovascular effects.


Q: Can Montril cause weight gain or loss?

Based on the reported data from clinical studies, Montril has not been reported to cause weight gain or loss. Concerns about unexpected changes in weight are typically reviewed by a healthcare provider, as weight changes are generally not a recognized effect of this medication.


Q: What should I do if I think Montril is not working for me?

Montril is intended for chronic, continuous use to help manage long-term conditions. If there are any concerns about whether the medication is providing the expected benefit or if symptoms change, these concerns about the medication's effect are typically reviewed by the prescribing healthcare provider for clinical assessment.


Q: Can taking Montril affect the results of blood tests?

Regulatory safety documents indicate that Montril has been reported to cause an increase in bleeding tendency and a decrease in eosinophils (a type of white blood cell) during studies. These changes in blood composition are typically monitored clinically when necessary.


Q: Does Montril affect driving or operating machinery?

The official product information notes that uncommon side effects such as dizziness and sleep disorders may occur. Awareness of individual response is noted as important, particularly before performing tasks that require concentration, such as driving or operating heavy machinery.


Q: Can Montril cause dry mouth or changes in taste?

Official safety documentation lists the range of possible side effects. Dry mouth (xerostomia) and changes in taste (dysgeusia) are not typically listed among the common or uncommon adverse reactions for this medication.


Q: What does official guidance say about stopping Montril suddenly?

Regulatory guidance emphasizes that the medication is for chronic, continuous maintenance treatment and should not be stopped abruptly, even if symptoms appear well-controlled. In conditions like asthma, Montril must also not be abruptly substituted for other corticosteroid treatments.


Q: Why is Montril sometimes referred to as a 'maintenance' medication?

Montril is prescribed for the chronic treatment and prophylaxis of asthma and for continuous relief of perennial allergic rhinitis symptoms. It is given once daily for long-term use, intending to stabilize chronic conditions rather than treating acute episodes.


Q: What are the reported side effects of Montril in children?

In children, common side effects reported more frequently than with placebo include upper respiratory infection, headache, and abdominal pain. Regulatory documents also highlight that serious, though less frequent, adverse reactions including neuropsychiatric events have been reported in pediatric patients.


Q: Can Montril be used by people who have kidney issues?

Yes, regulatory documents indicate that Montril is primarily eliminated through the bile, and no dosage adjustment is considered necessary for patients with renal insufficiency (kidney impairment). The standard dosage applies.


Q: Does the research on Montril show any long-term effects?

Research has studied the medication's safety and efficacy over defined periods. However, the FDA has issued a Boxed Warning regarding the risk of serious neuropsychiatric events (mood and behavior changes) based on reports, which can occur during or after discontinuation of treatment.


Q: Is there a generic version of Montril available?

Yes. The active ingredient in Montril, montelukast, is available from several manufacturers as an FDA-approved generic product. Generic montelukast is available in the same dosage forms and strengths as the original brand-name drug.


Q: Do older adults (seniors) need a different dose of Montril?

Official product information states that no dosage adjustment is considered necessary for older adults. The standard adult daily dosage of 10 mg is used for this population.


Q: Why do people sometimes stop taking Montril?

Official regulatory data on adverse events list certain side effects that may lead to the interruption or cessation of treatment. The most serious events are related to neuropsychiatric changes, such as mood changes and agitation, and these changes generally require clinical review.


Q: Are there specific symptoms that Montril helps with the most?

Montril is approved for the chronic management of asthma symptoms and for the relief of both daytime and nighttime symptoms of seasonal and perennial allergic rhinitis. Research has examined its impact on functional lung measures and patient-reported symptoms like nasal congestion and sneezing.


Q: Are there any known interactions between Montril and common herbal supplements?

Official drug documents detail known drug-drug interactions involving the P450 enzyme system, but they often do not contain specific data regarding most herbal remedies and supplements. Healthcare providers are typically kept informed about all products being taken due to the potential for interactions.


Q: How quickly does Montril leave the body after the last dose?

Montril is eliminated almost entirely via bile. The mean plasma half-life (the time it takes for the amount of drug in the body to be reduced by half) is relatively short, ranging from approximately 2.7 to 5.5 hours in healthy young adults.


Q: Is Montril used for any conditions other than the main ones listed?

Montril is officially approved for the chronic treatment of asthma, the acute prevention of exercise-induced bronchoconstriction (EIB), and the relief of allergic rhinitis symptoms. Official regulatory documents only define its use for these labeled indications.


Q: Why is it important to take Montril regularly?

The drug is intended for chronic, continuous maintenance treatment to provide sustained antagonism of the leukotriene receptor. This regularity is necessary to manage the underlying chronic inflammation and stabilize pulmonary function over time.


Q: Is Montril a non-addictive medication?

Montril is classified as a prescription drug (Rx) and is not listed as a controlled substance by regulatory bodies like the US DEA or international equivalents. This status indicates that it does not have a recognized potential for abuse or addiction.


Q: What is the risk of a serious allergic reaction to Montril?

Hypersensitivity reactions, including less common serious events like anaphylaxis (a severe allergic reaction), are reported in official safety documents. Montril is contraindicated (must not be used) in patients with a known hypersensitivity to any component of the drug.


Q: Does Montril have a maximum recommended usage period?

For its main uses in asthma and allergic rhinitis, Montril is intended for chronic, continuous use. Official regulatory documents do not define a specific maximum duration of treatment.


Q: Are there common warning signs associated with Montril use that patients should know?

The most serious warnings relate to neuropsychiatric events (including mood changes, agitation, sleep problems, and suicidal thoughts/behavior). Changes in mood or behavior are noted as important observations that may require immediate clinical evaluation if they occur.


Q: Why is Montril sometimes given as part of a combination therapy?

Montril can be added to a patient's existing treatment regimen, such as inhaled corticosteroids. It provides a distinct mechanism of action—leukotriene blockade—that supplements the effects of other medications to help manage symptoms.


Q: Do studies suggest Montril is equally effective for men and women?

Regulatory documents indicate that the pharmacokinetics (how the body processes the drug) are similar in males and females. Therefore, the same standard dosage applies for both genders.


Q: What are the official sources for information about Montril?

The most complete and authoritative information comes from national regulatory bodies, including the US Food and Drug Administration (FDA) drug label, the European Medicines Agency (EMA) Summary of Product Characteristics (SmPC), and the National Institutes of Health (NIH) MedlinePlus.


Q: Can Montril be crushed or split?

The standard film-coated tablets must be swallowed whole and should not be chewed, crushed, or split. Only the chewable tablets are designed to be chewed, and the granules are designed to be mixed with soft food.


Q: What kind of research has been done on Montril's use in younger people?

Clinical trials and safety studies have been conducted specifically in pediatric patients across all age groups for which the drug is approved (from 6 months to 14 years). This research established the appropriate safety profile and effectiveness for approved conditions in children.


Q: Is the effectiveness of Montril reduced over time?

Montril is intended for chronic, continuous use to provide long-term maintenance. Regulatory documents do not commonly cite a loss of effectiveness (tolerance or tachyphylaxis) over time for the labeled indications, suggesting sustained symptom management is expected.


Q: What happens if Montril is taken with common pain relievers like ibuprofen?

Interaction studies with Montril have not shown a clinically significant interaction with common non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. However, Montril is often noted to be used with caution in patients with known aspirin sensitivity who must continue to avoid aspirin and NSAIDs.

How should Montril be stored and disposed of?

Montelukast sodium must be stored under specific regulatory conditions to maintain stability and effectiveness.

Required Storage Conditions

Condition Requirement (Official Labeling)
Temperature Store at Controlled Room Temperature (20 C to 25 C / 68 F to 77 F).
Protection Keep in the original container/package to protect the product from light and moisture.
Child Safety Keep out of the reach of children.
Granule Stability Granules must be administered within 15 minutes of opening the sachet and must not be stored after mixing with food.

Official Disposal Instructions

Unused or expired product should be discarded using a drug take-back program. If a program is unavailable, mix the medication with an undesirable substance (e.g., dirt, coffee grounds) in a sealed bag before placing it in the household trash. The product must not be flushed down the toilet or disposed of in wastewater.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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