Zespira

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

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 Zespira

Property Description
Active ingredient Montelukast (as Montelukast sodium)
Form Oral (tablets, chewable tablets, granules)
Pharmacological class Leukotriene Receptor Antagonist (LTRA)
Common use Maintenance therapy for airway stability
Origin Synthetic compound

Zespira: Classification and Core Identity

Zespira is a prescription-only medication containing the active ingredient Montelukast (INN). It is defined pharmacologically as a Leukotriene Receptor Antagonist (LTRA), a specialized class of drugs designed to inhibit the action of specific inflammatory mediators. Montelukast is a synthetic compound manufactured through chemical processes and supplied strictly as a single-ingredient product, which is a distinguishing factor in its clinical application. This classification is clinically recognized for its role in modulating the long-term inflammatory response in the airways. The drug provides a crucial element of control in a typical long-term respiratory management scenario.

The Active Ingredient: Montelukast Sodium and its Forms

The chemically active component is Montelukast sodium, which is the salt form of Montelukast. Zespira is exclusively intended for oral administration, differentiating it from inhaled treatments. It is available in three distinct dosage forms: film-coated tablets for standard consumption, palatable chewable tablets, and oral granules. The availability of these varied forms represents a unique feature that accommodates different patient groups, including pediatric patients, who may have difficulty swallowing traditional solid medications. Montelukast is indicated for maintenance treatment.

General Purpose: Maintenance of Airway Stability

The fundamental purpose of Zespira is to act as maintenance therapy, providing continuous support for sustained, stable breathing through its foundational action on inflammatory pathways. By blocking the CysLT1 receptor, the drug generally helps to reduce the underlying, chronic inflammatory activity that contributes to airway hyper-responsiveness. Its general benefit is therefore preventative and foundational, serving to stabilize the respiratory environment and mitigate the body's over-reactive response to inflammatory triggers, supporting long-term airway health.

What side effects are possible with Zespira?

Possible side effects and safety information

The official safety profile for Zespira (Montelukast) is structured by government regulatory agencies using standardized frequency and System-Organ Class (SOC) classifications to communicate adverse events.

Category Regulatory Terminology
Key Adverse Reaction Categories Adverse reactions are classified by frequency and grouped by System-Organ Class (SOC). Key SOC classes include Psychiatric disorders, Infections and infestations, and Gastrointestinal disorders.
Frequency Classification Very Common (geq1/10 patients): Upper respiratory infection. Common (geq1/100 to <1/10): Headache, Pharyngitis, Abdominal pain, Diarrhoea, Nausea, Vomiting, Elevated serum transaminase levels.
Serious Adverse Reactions Clinically significant adverse reactions include neuropsychiatric events (such as suicidal thinking and behavior, aggression, and depression) and systemic eosinophilia, which can sometimes present with features of vasculitis consistent with Churg-Strauss syndrome. Hepatitis has also been documented.
Population-Specific Safety The chewable tablet forms contain phenylalanine and require specific consideration for patients with Phenylketonuria (PKU). The safety profile has not been evaluated in patients with severe hepatic impairment.
Safety-Related Restrictions The medication is contraindicated in individuals with known hypersensitivity to the product. It should not be abruptly substituted for inhaled or oral corticosteroids. Patients with known aspirin sensitivity should continue avoidance of aspirin or other NSAIDs.
Exposure-Related Pattern Regulatory reporting indicates that neuropsychiatric symptoms may persist even after the medicine has been discontinued.

Regulatory Safety Summary:

The safety profile distinguishes between frequently reported reactions (like upper respiratory infection) and rare, serious events (like neuropsychiatric changes). This classification ensures that users are aware of the full systemic scope of potential adverse effects, including those involving the Nervous and Psychiatric disorders classes. The constraints emphasize that the drug is not intended to replace systemic corticosteroid therapy and highlight specific population considerations related to PKU and severe liver function.

Overdose and Emergency Response

Overdose and when to seek help

Overdose Scope Official Regulatory Information
Documented Manifestations Clinical reports of acute overdose have frequently included presentations such as abdominal pain, somnolence (drowsiness), thirst, headache, vomiting, and psychomotor hyperactivity.
Exposure Context Acute overdose has been documented following ingestion of doses as high as 1000 mg in adults, with similar reports existing for children.
Severity and Risk Overdose cases, including those involving high single doses, have generally not been associated with serious or life-threatening adverse events. The observed findings were consistent with the medicine's established safety profile.
Antidote Availability The official prescribing information states that no specific antidote is known for Zespira (Montelukast).

Emergency Response and Required Actions

  • Immediate Medical Help: Patients and caregivers are required to seek immediate medical attention or consult emergency services for any suspected overdose event.
  • Supportive Management: The treatment approach, as defined in regulatory documents, is strictly symptomatic and supportive.
  • Procedural Note: Regulatory documents note that the drug and its metabolites are not significantly removed by dialysis, indicating that this procedure is negligible for elimination.
  • Population Notes: Overdose profiles in adults and pediatric patients have shown consistent clinical findings, with no unique population-specific severity risks explicitly documented.

Therapeutic Uses of Zespira

Montelukast is commonly used for the chronic control and management of symptoms across three key therapeutic areas. The medication plays a foundational role in managing conditions characterized by periods of heightened symptoms and inflammatory or irritative processes.

Zespira is relevant for long-term symptomatic support for persistent asthma, allergic rhinitis (both seasonal and perennial), and the management of exercise-triggered breathing difficulty (EIB). This controller medication helps maintain a sense of stability for lower airway symptoms like wheezing, chronic coughing, and chest tightness that interfere with daily functioning.

“This medication is primarily relevant for easing symptoms that are recurrent or chronic, supporting the patient during difficult episodes by helping to ease distress.”

This application contributes to easing the overall symptom load and supports general well-being. It is applied to address symptom clusters such as nasal congestion, runny nose, sneezing, and associated itchy, watery eyes, providing supportive relief. For episodic challenges like EIB, Zespira may assist with maintaining functional stability when physical activity causes symptoms.

Quick Fact: Relief for Chronic Airway and Allergic Symptoms Zespira is often used during phases when symptoms become more noticeable, providing support that helps ease the overall symptom burden across the upper and lower airways.

Regulatory References

  1. NIH MedlinePlus overview on Montelukast

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Zespira — Official Regulatory Information


Eligibility Scope

Category Official Regulatory Statement
Populations for whom use is allowed Adults and adolescents 15 years. Pediatric use established for asthma 12 months and perennial allergic rhinitis 6 months. No adjustment for renal or mild-to-moderate hepatic impairment.
Populations for whom use is contraindicated Patients with known hypersensitivity to Montelukast or any excipient. Must not be used for the reversal of bronchospasm in acute asthma attacks.
Age-related eligibility rules Safety and effectiveness are not established for asthma in patients less than 12 months or for EIB prevention in patients less than 6 years. No dosage adjustment is required for the elderly.
Pregnancy and lactation eligibility status Use is restricted and documented as "only if clearly needed" or "clearly essential" during pregnancy and lactation.
Eligibility-related restrictions Chewable tablet formulation is restricted for Phenylketonuria (PKU) patients due to phenylalanine content. Use for allergic rhinitis is reserved for patients intolerant to or inadequately controlled by alternative therapies.

Eligibility Classifications (High-Level)

Classification Official Regulatory Statement
Eligibility severity classification Contraindicated (e.g., Hypersensitivity), Warning/Precaution (e.g., PKU, Allergic Rhinitis Use), Not Established (Minimum Age Thresholds).
Regulatory basis Based on official governmental prescribing documents (e.g., FDA Prescribing Information and EMA Summary of Product Characteristics).
Eligibility-context constraints Use is limited by patient age, underlying metabolic disorders, and the acute versus chronic nature of the respiratory condition.

Resulting Eligibility Structure

Official eligibility statements:

  • Use is contraindicated in patients with a known hypersensitivity to the medicine.
  • The medicine must not be used to treat acute asthma attacks.
  • Eligibility is strictly defined by minimum age, such as 12 months for asthma and 6 months for perennial allergic rhinitis.
  • Use during pregnancy and lactation is restricted and authorized only when deemed clearly essential.

Connection to the overall eligibility profile: The official regulatory documents define Zespira's eligibility profile through absolute contraindications that strictly prohibit use in certain situations and through age-based thresholds that limit use until specific safety and effectiveness are established. Conditional use is required for patients with metabolic disorders and during pregnancy/lactation.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Zespira's (montelukast) interaction profile is primarily defined by its metabolism through certain Cytochrome P450 (CYP) enzymes, chiefly CYP2C8, along with contributions from CYP2C9 and CYP3A4.


Pharmacokinetic Exposure Modification

  • Increased Exposure: Co-administration with the potent CYP2C8 inhibitor Gemfibrozil significantly increases the systemic exposure (AUC) of Zespira, documented to be up to 4.4-fold higher. Although a routine dosage adjustment is not universally required, awareness of this interaction is necessary, particularly regarding potential for increased adverse effects.
  • Decreased Exposure: Potent enzyme inducers, such as Rifampicin (Rifampin) and Phenobarbital, may decrease Zespira's plasma concentrations. Co-administration with these inducers requires caution and clinical monitoring, especially in children, due to potential reduction in effectiveness.

Clinically Insignificant Interactions

Official studies have documented that Zespira does not produce clinically important changes in the pharmacokinetics of many common co-administered medicines, including Theophylline, Warfarin, Prednisone, and Oral Contraceptives (containing norethindrone/ethinyl estradiol).

Specific Interaction Constraints

Patients with documented aspirin sensitivity must continue to avoid aspirin and other non-steroidal anti-inflammatory agents (NSAIDs) while taking Zespira, as the drug is not intended to prevent the bronchoconstrictor response caused by these substances.

Mechanism of Action

Zespira (montelukast) functions as a leukotriene receptor antagonist. Its primary biological target is the cysteinyl leukotriene type-1 receptor ( CysLT1 receptor), which is prevalent on airway smooth muscle cells, macrophages, and pro-inflammatory cells like eosinophils.

The interaction type is one of competitive antagonism. Montelukast binds to the CysLT1 receptor with high affinity, thereby sterically preventing the binding and subsequent activation by endogenous cysteinyl leukotrienes ( LTC4, LTD4, and LTE4). The drug exhibits no agonist activity at this receptor.

At the molecular and intracellular pathways level, this antagonism blocks the G protein-coupled signal transduction cascade typically initiated by the leukotrienes. This action inhibits downstream signaling responsible for increasing intracellular calcium and other pro-inflammatory second messengers.

Consequently, the downstream cascades involving airway smooth muscle cell contraction, microvascular permeability, and the recruitment of eosinophils are modulated. The system-level physiological consequence is the modulation of airway tone and reduction of associated cellular infiltration and fluid extravasation in the respiratory system.

Dosage and Administration Information

How Zespira (Montelukast) is Used: Official Administration Guidelines

Zespira is strictly approved for oral administration across all available formulations: film-coated tablets, chewable tablets, and oral granules. It functions as a long-term, continuous maintenance treatment and is not intended for the acute reversal of severe breathing difficulties.

Standard Dosing and Timing

Administration is generally once daily, with the precise timing dependent on the condition being addressed. For the maintenance of airway stability in asthma, Zespira is typically administered in the evening. When used for isolated perennial or seasonal allergic rhinitis, the dose can be taken in the morning or evening. The medication may be taken with or without food.

Age Group Approved Dosage Strength Dosing Frequency
Adults and Adolescents (≥ 15 years) 10 mg (Film-Coated Tablet) Once daily, continuously
Pediatric (6 to 14 years) 5 mg (Chewable Tablet) Once daily, continuously
Pediatric (6 months to 5 years) 4 mg (Chewable Tablet or Granules) Once daily, continuously

Special Administration Instructions

For the prevention of exercise-induced bronchoconstriction (EIB), a 10 mg dose must be taken as a single administration at least two hours before exercise. This prophylactic dose should not be taken within 24 hours of a previous daily dose if the patient is already on chronic treatment. No dosage adjustment is necessary for older adults or patients with mild to moderate kidney or liver impairment.

Oral granules must be mixed with specific soft foods or liquids (like applesauce or baby formula) and the full dose consumed within 15 minutes of opening the packet. If a daily dose is missed, the standard instruction is to take the next scheduled dose at the regular time without doubling the dose.

Recent Clinical Evidence

Research evidence / Overview of studies for Zespira

Evidence for use in Persistent Asthma

The evidence base for Zespira's role in the chronic management of persistent asthma consists primarily of numerous Randomized Controlled Trials (RCTs) and Systematic Reviews that evaluate the trial results. Zespira was studied for persistent asthma in populations including adults, adolescents, and children, down to one year of age.

Researchers were primarily interested in outcomes monitoring physiological strain related to breathing, such as objective measurements of lung function (like FEV1), and patient-reported outcomes describing perceived discomfort associated with asthma symptoms. What the studies reported is that trials reported measurements of changes in lung function over the study periods. Findings describe patterns observed in the studies related to the use of rescue medications.

Evidence for use in Exercise-Triggered Breathing Difficulty

Research related to breathing difficulty triggered by exercise was evaluated in controlled, placebo-based RCTs. Zespira was observed in patient groups starting from children six years of age up through adults. The main measurement in these studies was the degree of change monitored during bronchoconstriction assessments, quantified by measuring lung function drops after exercise. Research describes patterns observed in the studies related to outcomes reflecting daily functioning after exercise when the compound was observed in patients administered daily dosing. Data for certain groups remain insufficient, particularly children younger than six years old for this specific indication.

Long-Term Studies and Follow-up Duration

Because the conditions Zespira was studied for are conditions characterized by fluctuating or episodic manifestations, there is limited information for long-term outcomes regarding the sustained effects of daily use over the course of multiple years. The majority of the available research base involves trials conducted over short-to-intermediate timeframes, typically ranging from a few weeks to several months. Therefore, the long-term effects are not fully established, and this is an area where data are still emerging and research is ongoing.

Key Studies & References

  1. NIH MedlinePlus overview on Montelukast
  2. Montelukast for preventing exercise-induced bronchoconstriction in patients with asthma: a systematic review and meta-analysis

Frequently Asked Questions (FAQ)

Common questions about Zespira (FAQ)


Q: Why is Zespira available only by prescription?

A: Zespira is designated as a prescription-only medication because the chronic conditions it addresses require professional diagnosis and monitoring by a healthcare provider. Regulatory agencies, such as the FDA, have issued a Boxed Warning, emphasizing the potential for serious mental health side effects and the need for clinical oversight.

Q: Does Zespira interact with common over-the-counter pain relievers?

A: Official interaction studies have documented that Zespira does not produce clinically significant changes in the pharmacokinetics when taken with common over-the-counter pain relievers like acetaminophen. However, regulatory guidance advises that patients with documented aspirin sensitivity must continue to avoid aspirin and other non-steroidal anti-inflammatory agents (NSAIDs).

Q: Can Zespira affect the results of common laboratory blood tests?

A: Regulatory safety information lists elevated serum transaminase levels as a common adverse reaction, which is measured by a blood test for liver function. Studies examining other common laboratory procedures, such as skin prick tests, have reported that they are unaffected by the medication.

Q: Is it okay to stop taking Zespira suddenly?

A: Official guidance addresses stopping Zespira primarily in specific situations. For instance, if neuropsychiatric symptoms occur or worsen, regulatory guidance advises discontinuing the treatment. Separate guidance specifies that Zespira is not intended to be an abrupt substitute for inhaled or oral corticosteroids.

Q: Do regulatory agencies classify Zespira as a high-risk drug?

A: Regulatory agencies, including the FDA, have placed a Boxed Warning on Zespira’s prescribing information. This safety alert is used to emphasize the potential risk of serious mental health side effects, including suicidal thoughts and behavior, highlighting the possibility of serious adverse events that require careful patient consideration.

Q: Are there certain groups of people for whom Zespira is considered less effective?

A: Regulatory guidelines for conditions like asthma in certain populations, such as children five years of age or younger, position Zespira as an alternative therapy rather than the initial preferred controller. Additionally, its use for allergic rhinitis is often reserved for patients who have an inadequate response to or intolerance of alternative treatments.

Q: What is the evidence regarding Zespira's effect on quality of life?

A: Research studies supporting the use of Zespira included patient-reported outcomes to measure treatment effect. These outcomes document changes in how patients perceive their symptoms and manage discomfort, which informs the overall evidence base regarding the drug's impact on daily functioning.

Q: Is there a generic version of Zespira available?

A: Yes, Zespira contains the active ingredient montelukast. The medication is approved and available under this generic name from multiple manufacturers, in addition to its various brand-name forms.

Q: Why do some people say they felt tired after taking Zespira?

A: Regulatory documents and post-marketing surveillance reports list drowsiness and dizziness as potential nervous system adverse effects. These symptoms may be described by individuals as feeling tired after taking Zespira.

Q: How quickly should someone expect Zespira to start working?

A: The therapeutic effect of Zespira on key measurements of asthma control is documented in clinical information to occur within one day of beginning treatment.

Q: Does Zespira change how my body processes food or drink?

A: Official administration guidelines state that Zespira may be taken with or without food. This instruction confirms that the medication can be administered without reference to meal timing.

Q: Are there any specific foods I should avoid while using Zespira?

A: Regulatory instructions state the medication can be taken with or without food. Official product information and interaction studies do not list any specific food groups or common ingredients that must be avoided while using Zespira.

Q: Do studies mention Zespira's potential effect on sleep patterns?

A: Regulatory safety information specifically mentions the possibility of sleep-related issues as potential neuropsychiatric events. These events can include difficulty sleeping (insomnia) and reports of sleep-walking that have been documented.

Q: Are there any known issues with taking Zespira while driving?

A: Official product information states that Zespira has no or negligible influence on the ability to drive or operate machinery. However, individuals have reported experiencing side effects such as drowsiness or dizziness. These side effects are important to note before driving or operating machinery.

Q: What should be done if someone experiences an unexpected reaction after taking Zespira?

A: Regulatory agencies instruct patients and caregivers to be vigilant for new or worsening adverse reactions while taking the medication. Official guidance includes the instruction to seek medical advice immediately and contact a health care professional if serious symptoms occur.

Q: Is Zespira related to any other drug names I might have heard of?

A: Zespira contains the active ingredient montelukast, which is the same ingredient found in the original brand-name drug Singulair. The active ingredient is also available under various other generic brand names worldwide.

Q: Does alcohol consumption affect how Zespira works in the body?

A: While official interaction studies do not list a specific drug interaction with alcohol, post-marketing reports of liver injury in patients taking Zespira have been documented. This was noted particularly in those with underlying risk factors for liver disease, such as a history of alcohol use.

Q: Is Zespira classified as a controlled substance?

A: Official classification documents from regulatory bodies indicate that Zespira (montelukast) is not classified as a controlled substance. It is categorized as a standard prescription drug.

Q: How long after taking Zespira does it typically stay in the body?

A: Montelukast has a half-life of approximately 2.7 to 5.5 hours, which describes the time it takes for half of the drug to be processed. The drug and its related metabolites are documented in pharmacokinetic information to take up to a couple of days to be fully eliminated from the body.

Q: What is the risk of dependence or addiction described for Zespira?

A: Official drug classification documents indicate that Zespira (montelukast) is not associated with properties that lead to dependence or potential for abuse. The medication is not considered to have an addictive risk.

Q: Do clinical guidelines mention specific lifestyle changes alongside Zespira?

A: Regulatory guidance for preventing breathing difficulty triggered by exercise requires a specific condition of use. The guidance describes a single administration of Zespira at least two hours before exercise, which is a use constraint related to a specific activity.

How should Zespira be stored and disposed of?

Official Storage and Disposal Requirements

Zespira (Montelukast) requires specific storage and handling as defined by regulatory labeling to maintain product stability and safety.

Storage Category Requirement
Temperature Store below 25 C (77°F).
Protection Keep in the original package to protect from light and moisture.
Stability If supplied in an HDPE bottle, discard the medicine 30 days after the first opening.
Safety Keep the medicine out of the sight and reach of children.

Disposal instructions mandate that any unused or expired Zespira must be discarded in accordance with local requirements for pharmaceutical waste.

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

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