Stopaler

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Medically reviewed

Marina Burgos

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 Stopaler

What is Stopaler? An Overview

Property Description
Active Ingredient Cetirizine Hydrochloride
Form Oral solution, Film-coated tablet
Pharmacological Class Second-generation H1 Antihistamine
General Purpose Anti-allergic agent
Origin Synthetic substance (metabolite of Hydroxyzine)

What Type of Medicine is Stopaler? (Classification and Identity)

Stopaler is a medicinal product whose active ingredient is Cetirizine Hydrochloride, scientifically classified as a selective, second-generation antihistamine and an H1 receptor antagonist. This compound is a synthetic substance chemically derived as a carboxylic acid metabolite of the older drug, Hydroxyzine. Official pharmacopeias recognize its role in managing allergic responses. This classification is clinically recognized for providing targeted relief, differing from first-generation drugs by aiming to minimize systemic effects like drowsiness.

As a second-generation antihistamine, Stopaler represents a modern class of anti-allergic medication developed for targeted action. It is a single-ingredient product whose classification signifies that its primary mechanism is highly focused on blocking the activity of histamine, which is the key chemical mediator of allergic and hypersensitivity reactions. This selective design is crucial for delivering effective relief while minimizing potential systemic effects associated with older classes of allergy medicines.


Composition and Physical Forms

The active ingredient in Stopaler is Cetirizine Hydrochloride, which is supplied for systemic administration via the oral route. The medicine is commonly available in pharmaceutical preparations, including the film-coated tablet and the oral solution. The oral solution form is often favored for easier titration in pediatric patient groups or for individuals who have difficulty swallowing solid tablets.

The composition consists of the main therapeutic substance, Cetirizine Hydrochloride, combined with appropriate non-active components, or excipients. These excipients may be solid excipients for the tablet form or an aqueous vehicle for the liquid form. The medicine is classified as an agent for relieving hypersensitivity symptoms. It provides relief by addressing the chemical processes that cause allergic discomfort, which is particularly useful for managing seasonal discomfort.


What is the General Purpose of Stopaler? (High-Level Benefit)

The general purpose of Stopaler is to act as an effective anti-allergic agent by counteracting the body's reaction to allergens. It functions by selectively preventing the attachment of histamine to peripheral H1 receptors, thereby providing relief from the symptoms associated with allergic conditions. This blockade suppresses the body's inflammatory and hypersensitivity responses. A key characteristic of the second-generation classification is that Cetirizine Hydrochloride is considered relatively non-sedating when used at the identity level, making it suitable for managing symptoms during typical daytime activities.

What side effects are possible with Stopaler?

Possible side effects and safety information

The safety profile of Stopaler (Cetirizine) is categorized by government regulatory bodies using standardized frequency terminology and system-organ classes (SOC) based on clinical trials and post-marketing surveillance. This structure documents both the most frequent and the most clinically significant adverse events.

Adverse Reaction Frequencies

Adverse reactions are classified by their documented occurrence rates:

  • Common (e.g., in at least 1 in 100 people): Somnolence (drowsiness), fatigue, headache, dizziness, dry mouth, nausea, and pharyngitis (sore throat).
  • Uncommon (e.g., in less than 1 in 100 people): Pruritus (itching), rash, and agitation.
  • Rare (e.g., in less than 1 in 1,000 people): Reactions of hypersensitivity, tachycardia (increased heart rate), and hepatic function abnormal (elevated liver enzymes).
  • Very Rare (e.g., in less than 1 in 10,000 people): Thrombocytopenia (low platelet count), anaphylactic shock, and urinary retention.

System-Organ Classes and Serious Events

Documented effects are grouped by body system, including Nervous System Disorders, Gastro-intestinal Disorders, and Immune System Disorders. Serious adverse reactions officially documented include anaphylactic shock (Very Rare) and hypersensitivity reactions (Rare).

Population and Exposure-Related Safety Notes

The official labeling defines specific safety constraints. Stopaler is contraindicated in individuals with end-stage renal impairment (Creatinine Clearance <10 mL/min), and dose adjustment is required for all other levels of renal impairment. Caution is advised for individuals with a predisposition to urinary retention or for epileptic patients due to the potential for convulsions. Furthermore, severe, generalized pruritus has been reported following the discontinuation of long-term daily use, typically occurring within a few days of stopping the medicine.

Overdose and Emergency Response

Overdose and When to Seek Help

Overdose Context and Symptoms

An overdose may initially present with non-specific and potentially limited symptoms such as nausea, vomiting, and abdominal pain. It is critical to understand that the absence of severe symptoms in the early stage does not rule out serious toxicity. The most significant and potentially fatal outcome is delayed liver damage (hepatic necrosis), which can progress to hepatic failure, encephalopathy, coma, and death.

When to Seek Immediate Medical Help

Immediate medical attention must be sought in the event of any suspected overdose, regardless of whether the patient currently feels well or exhibits noticeable symptoms. The risk of severe, delayed liver injury is present even with minimal early signs. Patients should be transported to a hospital urgently for professional medical assessment and treatment. This immediate action is essential because the effectiveness of specific overdose management procedures, such as the administration of the antidote N-acetylcysteine, is significantly reduced if treatment is delayed beyond a few hours.

Risk Factors and Management

The risk of severe poisoning is increased in patients with pre-existing liver disease, chronic alcoholism, or malnutrition, and in young children. Hospital management typically involves urgent administration of the antidote, administration of activated charcoal if ingestion was recent, and continuous monitoring of laboratory and physiological parameters to manage the risk of organ failure.

Therapeutic Uses of Stopaler

What Stopaler Treats: Main Uses and Benefits

Stopaler (Cetirizine) is a medication commonly used for managing symptoms related to inflammatory or irritative states caused by allergic reactions. It provides support that helps ease the overall symptom burden and plays a role in managing conditions characterized by periods of heightened symptoms. As an established treatment, its therapeutic relevance is recognized in areas where additional symptomatic support is needed.

The medication is primarily used for managing allergic rhinitis (seasonal and perennial hay fever), chronic urticaria (hives), and allergic conjunctivitis. It helps address groups of symptoms that may become intense or disruptive, such as frequent sneezing, profuse runny nose, intense itching, and the appearance of red welts.

“A key benefit of this medication is providing support for prolonged symptom management and may assist with maintaining functional stability during allergic episodes.”

This supportive treatment may assist with maintaining functional stability and may help patients cope more steadily with symptom fluctuations, contributing to improved comfort during symptomatic periods.


Quick Fact: Relief for Pruritus Stopaler is generally applied in scenarios where additional management of discomfort is appropriate for conditions presenting with severe pruritus (skin itching), which is often a very disruptive symptom of chronic urticaria.

Regulatory References

  1. NIH StatPearls overview on Cetirizine

Eligibility and Restrictions for Use

Who Can and Cannot Use Stopaler? Official Eligibility Profile

The eligibility for using Stopaler (Cetirizine Hydrochloride) is strictly defined by regulatory authorities based on age, known allergies, and specific health conditions. This information outlines the patient groups for whom the medicine is permitted, restricted, or absolutely contraindicated.

Absolute Contraindications

Stopaler must not be used by individuals with a known hypersensitivity to the active ingredient Cetirizine, its parent drug Hydroxyzine, or any related piperazine derivatives. Use is also contraindicated in patients with severe renal impairment or end-stage renal disease (Creatinine Clearance less than 10 mL/min) due to the risk of drug accumulation.

Restricted and Conditional Use

Population Group Regulatory Status and Limitation
Pediatric Patients Tablets are not recommended for children under 6 years. Use in infants under 6 months is not established for most oral forms.
Moderate Renal Impairment Patients with reduced kidney function (CrCl 10–50 mL/min) are a restricted population who require a reduced daily dose.
Pregnancy/Lactation Not recommended during pregnancy or breastfeeding unless deemed clearly necessary by a health professional.
Older Adults Generally permitted, but dose reduction may be required due to possible age-related decline in renal function.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory information identifies specific drug classes and substances that can interact with Stopaler (which contains a second-generation antihistamine), primarily through an additive effect on the central nervous system (CNS).

Interacting Drug Classes and Substances

Interaction Domain Mechanistic Basis Regulatory Constraint
Central Nervous System (CNS) Depressants Pharmacodynamic (additive CNS depression) Use with caution and monitor for increased drowsiness.
Alcohol Pharmacodynamic (additive CNS depression) Concomitant use is discouraged due to potential for further impaired alertness.
Theophylline Pharmacokinetic (reduced clearance of Stopaler) May necessitate close monitoring to manage increased systemic drug exposure.

Official Interaction Statements

  • Central Nervous System (CNS) Depressants: This class includes sedatives, tranquilizers, opioids, and certain other antihistamines. Concomitant use with Stopaler may result in additive effects, potentially increasing the risk of drowsiness, reduced alertness, and decreased mental function. Caution and monitoring are required if combined.
  • Alcohol: Avoid the use of alcoholic beverages while taking this medicine. The combination can heighten the CNS depressant effects of both substances.
  • Theophylline: Co-administration with theophylline (a medicine used for breathing problems) may lead to a modest decrease in the clearance of Stopaler from the body, potentially resulting in higher systemic levels. This pharmacokinetically significant interaction requires clinical consideration.

Population-Specific Notes

Official labeling indicates that patients with pre-existing impaired renal function or hepatic function may experience higher drug exposure, potentially increasing the risk or severity of interactions. These patients may require careful consideration when taking the medicine alongside any interacting products.

Mechanism of Action

Selective Peripheral H1-Receptor Antagonism

Stopaler's primary mechanism involves acting as a selective antagonist at the peripheral histamine H1 receptors. It competitively binds to these receptors, effectively blocking the attachment of the endogenous inflammatory mediator, histamine. This targeted interaction suppresses the initial histamine-driven signaling cascade in peripheral tissues, which modulates the magnitude of downstream mediator-driven cellular activation.


Limited Central Nervous System Penetration

The chemical structure of Stopaler results in limited capacity to cross the blood-brain barrier (BBB). This characteristic ensures the drug's activity is preferentially directed toward peripheral systems rather than central H1 receptors. Minimal occupancy of central H1 receptors dictates the drug's activity profile and influences the resulting pharmacological characteristics.


Anti-Inflammatory Mediator Modulation

Beyond direct H1 blockade, Stopaler engages mechanisms that regulate other molecular steps in the allergic cascade. This includes decreasing the propagation of mediator-driven signaling by modifying early molecular steps. This mechanism supports a more regulated state within targeted pathways in the body.

Dosage and Administration Information

How Stopaler is Used: Official Administration Guidelines

Stopaler, containing Cetirizine Hydrochloride, is administered according to specific guidelines. The medicine is primarily used via the oral route as a film-coated tablet or solution, but applications also include Intravenous (IV) injection for acute, monitored use and a Topical Ophthalmic solution for localized eye application.

Standard Dosing and Frequency

The standard oral regimen for adults and adolescents (age 12 and older) is a single dose of 5 mg or 10 mg, to be taken Once Daily. The maximum recommended oral dose is 10 mg per day. This once-daily frequency establishes a predictable schedule for systemic treatment. For oral forms, intake is flexible and can occur with or without food.

Procedural and Population Adjustments

Administration instructions differ by form. The IV injection must be administered as a slow push over a period of 1 to 2 minutes. Dosage adjustments are required for patients with reduced renal function to prevent drug accumulation, with the regimen potentially reduced to 5 mg every two days, depending on the degree of impairment. Specific age- and weight-dependent oral dosing schedules are defined for pediatric patients starting from six months of age.

Handling Missed Doses

If a scheduled oral dose is missed, the patient should not take a double dose to compensate. The patient should resume the original once-daily schedule at the usual time. The medicine may be used for a short duration to manage acute symptoms or as part of a longer-term plan, depending on the condition being addressed.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Stopaler (Cetirizine)


Evidence for use in Allergic Rhinitis (Hay Fever)

Research examined Stopaler concerning outcomes related to physical discomfort associated with allergic rhinitis, or hay fever. The research base relies on short-term Randomized Controlled Trials (RCTs) across Adults, Adolescents, and Pediatric patients. Researchers tracked symptom changes using the Total Symptom Score (TSS). Findings describe patterns observed where measured symptom changes were generally documented in controlled trial settings compared to a placebo. Follow-up durations were limited in many key trials, and long-term effects are not fully established regarding sustained consistency beyond approximately 12 weeks. Comparative data in certain head-to-head trials against all available agents are also limited.


Evidence for use in Chronic Urticaria (Hives)

Studies have explored the role of Stopaler in conditions characterized by fluctuating manifestations such as chronic urticaria. The evidence consists of RCTs and Systematic Reviews focused on outcomes related to physical discomfort, particularly intense itching (pruritus) and the appearance of welts (weals), monitored using the Urticaria Activity Score (UAS). Research also examined the use of doses that are higher than standard for patients whose symptoms were persistent. Data for certain groups remain insufficient, particularly concerning the long-term measured effect when the medicine is used in higher amounts.


Evidence Gaps and Limitations

The research contributes to the broader evidence landscape, but several limitations are noted. Long-term effects are not fully established across all indications, as the majority of key efficacy trials relied on follow-up durations being limited to acute or short-term periods. Furthermore, while pediatric patient groups were examined, the data available for large-scale, long-term outcomes in the very youngest children remain insufficient. Dedicated comparative studies focusing on older adults with complex health conditions are also limited.

Key Studies & References

  1. Cetirizine: Uses, Interactions, Mechanism of Action - DrugBank Online
  2. Label: CETIRIZINE HCL- cetirizine tablet (FDA Monograph/Indications) - DailyMed
  3. Chronic urticaria: off-label doses of cetirizine (NICE Evidence Summary on high-dose use)
  4. Cetirizine for the treatment of allergic diseases in children: A systematic review and meta-analysis - Frontiers in Pediatrics

Frequently Asked Questions (FAQ)

Common questions about Stopaler (FAQ)


Q: Does Stopaler help with nasal congestion or just sneezing?

A: Studies and official information indicate that the active ingredient in Stopaler is described in official documents for managing symptoms of allergic rhinitis. This includes addressing not only sneezing and itching, but also associated symptoms such as a runny nose and nasal congestion.

Q: How is Stopaler different from other common allergy tablets?

A: Stopaler is classified as a second-generation H1-antihistamine. According to regulatory documents, this class of medicines is designed to act more selectively on peripheral histamine receptors. This selective action has a classification designed for targeted action while demonstrating a more limited ability to cross the blood-brain barrier compared to older antihistamines.

Q: Can taking Stopaler potentially interfere with allergy skin tests?

A: Regulatory guidance notes that antihistamines can suppress the skin reaction caused by diagnostic allergy tests. Official documents suggest that the medicine may need to be discontinued for a specified period, typically several days, before a scheduled skin test.

Q: How long does the effect of a Stopaler dose usually last?

A: Based on clinical studies, a single dose of Stopaler has been documented to demonstrate anti-histaminic activity that was measured to persist for at least 24 hours. This duration aligns with the standard once-daily dosing regimen outlined in the official product information.

Q: Is it considered normal to experience dry mouth when taking Stopaler?

A: Dry mouth is a documented side effect of Stopaler. It is listed in official safety information as a Common adverse reaction, which means it has been reported to occur in at least 1 in 100 people during clinical use.

Q: Is there a generic version of Stopaler available for purchase?

A: The active ingredient in Stopaler, Cetirizine Hydrochloride, has received official approval through an Abbreviated New Drug Application (ANDA) from regulatory bodies. This indicates that generic versions of the medicine are officially marketed and available.

Q: Is Stopaler only for seasonal allergies?

A: Official labeling describes its use for managing symptoms associated with both seasonal allergic rhinitis (often called hay fever) and perennial (year-round) allergic rhinitis, as well as chronic hives (urticaria).

Q: Why do some people report feeling nervous or having trouble sleeping on Stopaler?

A: Official safety information for the medicine documents agitation as an Uncommon adverse reaction, and reports of trouble in sleeping have been noted in rare cases or in the context of overdose. These documented reactions reflect patterns of nervous system effects that have been reported.

Q: Are there any specific supplements or vitamins that should not be taken with Stopaler?

A: Regulatory guidance indicates that most herbal remedies and supplements are not systematically tested for interactions with the medicine. As a result, information on potential concurrent interactions is often limited or not explicitly established in official documents.

Q: Can Stopaler be taken with common pain relievers like Tylenol (Acetaminophen)?

A: Official drug interaction databases indicate that no known interactions were found when Stopaler (Cetirizine) is taken concomitantly with the common pain reliever Acetaminophen.

Q: Are there any food items that interact with Stopaler?

A: Official pharmacokinetic studies indicate that while taking the medicine with food may modestly delay the time it takes to reach its highest level in the bloodstream, it does not affect the overall amount of the medicine absorbed by the body.

Q: How long does it typically take for Stopaler to start working?

A: Clinical trial data describes that the onset of measurable anti-histaminic activity for a single dose has been documented to occur quickly, often within 20 minutes in a portion of individuals.

Q: Is Stopaler suitable for people who have heart conditions?

A: Regulatory clinical studies have examined the effect of the medicine on the heart's electrical activity. These studies reported that the medicine did not significantly prolong the QTc interval, a specific measure of cardiac electrical activity that was examined.

Q: How was Stopaler originally discovered?

A: Official information notes that Stopaler's active ingredient, Cetirizine, is a synthetic substance. It was chemically derived as a carboxylic acid metabolite of the older drug, Hydroxyzine.

Q: Why is Stopaler available by prescription in some places but over-the-counter in others?

A: This difference is due to the regulatory classification history in each country. In the United States, for example, the medicine was originally approved as prescription-only and later approved for over-the-counter use following a specific process of regulatory review and reclassification.

Q: Is it okay if I miss a dose of Stopaler sometimes?

A: Official guidance concerning a missed dose indicates that a double dose should not be taken to compensate. The patient should resume the original once-daily schedule at the usual time as described in the official product information.

How should Stopaler be stored and disposed of?

Storage and Protection Requirements

Stopaler (Cetirizine) must be kept out of the sight and reach of children as mandated by regulatory labeling.

Dosage Form Required Storage Conditions (Official Labeled)
Tablets Store at Controlled Room Temperature, typically 20 C to 25 C (68 F to 77 F). Protect from excess heat and moisture.
Oral Solution Do not store above 25 C. Keep the bottle tightly closed and protect from light.

The medicine should be stored in its original container until the expiry date. If using the oral solution, it must be used within 6 months after first opening the bottle, as specified by stability documents.

Official Disposal Rules

Do not dispose of Stopaler via wastewater or household waste, as this is prohibited by environmental safety regulations. Unused or expired product must be disposed of according to local pharmaceutical waste requirements; patients are instructed to ask a pharmacist for guidance on proper disposal.

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

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