Hisaler

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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 Hisaler

Understanding Hisaler

Hisaler is a medication categorized as an antihistamine. It is primarily used to manage symptoms associated with various allergic conditions. The active therapeutic component in Hisaler works by targeting specific histamine receptors in the body, which helps to mitigate the physiological responses typically triggered by allergens.

Primary Uses

Hisaler is commonly utilized for the relief of symptoms related to seasonal and perennial allergic rhinitis. These symptoms may include:

  • Sneezing
  • Nasal congestion or runny nose
  • Itching of the nose or palate
  • Red, itchy, or watery eyes

In addition to respiratory allergies, Hisaler is also indicated for the management of chronic idiopathic urticaria, a condition characterized by the regular appearance of itchy wheals or hives on the skin without an identifiable external cause.

Mechanism of Action

As a second-generation antihistamine, Hisaler is designed to provide systemic relief from allergy symptoms. It acts as a selective peripheral H1-receptor antagonist. By blocking these receptors, the medication prevents histamine—a chemical released by the immune system during an allergic reaction—from binding to its targets. This action reduces the localized inflammation and discomfort associated with allergic triggers.

Unlike earlier generations of antihistamines, this class of medication is formulated to have a limited ability to cross the blood-brain barrier. This characteristic is intended to minimize the impact on the central nervous system, often resulting in a lower incidence of sedation compared to older antihistamine variants.

What side effects are possible with Hisaler?

Possible Side Effects and Safety Information

The safety profile of Hisaler (Cetirizine Hydrochloride) is formally defined by regulatory authorities based on frequency classifications and specific patient constraints. Adverse reactions are grouped by System-Organ Class (SOC) to provide a clear regulatory overview.


Frequency-Classified Adverse Reactions

The most commonly reported adverse reactions documented in official regulatory documents include headache, somnolence (drowsiness), dizziness, fatigue, and dry mouth. These effects are generally classified as Common (may affect up to 1 in 10 people).

Less frequent, Uncommon reactions (up to 1 in 100) may include agitation, paresthesia, and rash. Rare reactions (up to 1 in 1,000) include tachycardia (increased heart rate), hypersensitivity reactions, and abnormal liver function (which is typically reversible).

Serious Adverse Reactions and Safety Patterns

Very Rare reactions (up to 1 in 10,000) documented in post-marketing surveillance include anaphylactic shock and convulsions. These effects are considered medically significant.

Regarding the timing of use, some common effects like somnolence may be more noticeable at the start of treatment. Additionally, official documents report cases of intense pruritus (itching) upon discontinuation of the medicine.

Population-Specific Constraints

Regulatory labeling establishes that dosage adjustments are necessary for patients with moderate to severe renal impairment dueable to the drug’s elimination characteristics. Hisaler is contraindicated in patients with a known hypersensitivity to the medicine, hydroxyzine, or any piperazine derivatives, and is not recommended for use in cases of severe renal failure (creatinine clearance less than 10 mL/ min).

Overdose and Emergency Response

Overdose and when to seek help

Regulatory documentation defines the overdose profile for Hisaler (Cetirizine Hydrochloride) based on documented clinical manifestations and required emergency actions.

Documented Overdose Manifestations

The most commonly reported signs of overdose include somnolence (drowsiness), headache, and dry mouth.

Physiological System Documented Manifestation
Central Nervous System Somnolence, Restlessness, Agitation, Convulsions (rare)
Cardiovascular Tachycardia (fast heart rate)

Serious systemic manifestations, such as convulsions and tachycardia, have been documented in official reports, primarily in cases of significant overexposure. Pediatric overdose is often characterized by restlessness and irritability followed by drowsiness.

Official Emergency Actions

In the event of an accidental or suspected overdose, regulatory guidance requires individuals to seek professional assistance immediately or contact a Poison Control Center right away.

Treatment for an overdose is exclusively symptomatic and supportive, as official labeling confirms that no known specific antidote to cetirizine exists. Management procedures may include gastric lavage if the ingestion was recent, though the substance cannot be effectively removed by dialysis.

Therapeutic Uses of Hisaler

What Hisaler Treats: Main Uses and Benefits

Hisaler is applied across domains where additional symptomatic support is needed, primarily for conditions involving allergic responses. This medicine is commonly used across conditions presenting with acute episodes or episodic manifestations.

Its core use is applied in addressing the symptomatic burden of seasonal and perennial allergic rhinitis (hay fever), which involves addressing persistent sneezing, runny nose, nasal itching, and associated itchy, watery eyes. It is also relevant in conditions characterized by periods of heightened symptoms, specifically Chronic Urticaria (hives) and generalized allergic pruritus.

Hisaler provides support that helps ease the overall symptom burden and assists with maintaining functional stability. This symptomatic assistance is also often used when symptoms intensify and supportive relief is needed for acute episodes like localized reactions to insect bites.


Quick Fact: Symptom Relief Focus

Category Focus of Symptomatic Support
Respiratory Sneezing, Rhinitis, Nasal Itching
Dermatologic Chronic Urticaria (Hives), Allergic Pruritus
Ocular Itchy and Watery Eyes

Eligibility and Restrictions for Use

Hisaler (Cetirizine Hydrochloride) eligibility is defined by official regulatory labeling across three main classifications: contraindicated, restricted, and established use.

The medicine is contraindicated (must not be used) in patients with severe renal impairment (end-stage kidney disease), typically defined as creatinine clearance below 10 mL/min or 15 mL/min. It is also strictly prohibited for individuals with a known hypersensitivity to the active substance, any excipients, or to related compounds like hydroxyzine or other piperazine derivatives.

For several populations, use is restricted or conditional. Patients with mild to moderate renal impairment require a formal dose adjustment based on the degree of reduced kidney function. Caution is formally recommended for epileptic patients and those with risk factors for urinary retention.

Use is established for adults and adolescents, and for children as young as six months (liquid formulations). However, the tablet form is not recommended for children under six years due to the inability to achieve appropriate dose adaptation. During both pregnancy and breastfeeding, use should only proceed with medical consultation and if considered necessary.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documentation details the potential for Hisaler (Cetirizine Hydrochloride) to engage in both pharmacodynamic and pharmacokinetic interactions.


Interaction Scope

Category Documented Interaction Statement
Pharmacodynamic Interactions Concurrent use with alcohol or other Central Nervous System (CNS) Depressants (e.g., sedatives, tranquilizers) may cause additive CNS effects, resulting in additional reductions in alertness and performance.
Pharmacokinetic Interactions Co-administration with Theophylline (400 mg once daily) resulted in a 16% decrease in cetirizine clearance, which may increase systemic exposure. Pharmacokinetic studies showed no clinically significant interactions with Ketoconazole, Erythromycin, or Pseudoephedrine.
Absorption Kinetics The rate of absorption is officially decreased by food, resulting in a reduction in peak plasma concentration, though the extent of overall absorption is not reduced.

Interaction-Related Constraints

Category Constraint/Condition
Procedural Timing A 3-day wash-out period is required before performing allergy skin tests to avoid inhibition of the testing procedure.
Population Specific Patients with renal impairment or hepatic impairment exhibit significantly decreased clearance and a prolonged half-life, which is a documented population-specific factor that increases exposure risk.

The regulatory profile defines Hisaler’s interaction structure primarily through cautions regarding additive CNS effects and specific pharmacokinetic modifications involving reduced drug clearance by co-administered substances. No medicinal products are explicitly designated as contraindicated with single-agent Cetirizine.

Mechanism of Action

Selective Blockade of Peripheral mathbfH1 Receptors

This core mechanism involves the drug acting as a highly selective antagonist at the peripheral histamine mathbfH1 receptor, found on tissues like blood vessels and sensory nerves. By binding to and inactivating this receptor, the drug suppresses the initial signaling cascade triggered by the release of endogenous histamine. This action is critical for limiting histamine's action on peripheral sensory nerve endings and on the capillary endothelium, and reversing histamine-induced changes in vascular permeability.


Minimal Central Nervous System (CNS) Activity

Cetirizine is structurally hydrophilic and acts as a substrate for P-glycoprotein, a transporter that actively pumps the drug out of the brain across the Blood-Brain Barrier (BBB). This process ensures minimal occupation of H1 receptors within the CNS, defining the mechanism as predominantly peripheral. This selectivity results in the mechanism being independent of the central histamine pathways.


️ Modulation of Inflammatory Cell Recruitment

The drug exhibits a secondary, non- H1 mechanism that modulates the inflammatory cascade by limiting the movement of certain immune cells. It is documented to inhibit the migration of eosinophils and neutrophils to sites of inflammation, and to suppress the release of some cytokines and other inflammatory mediators. This mechanism contributes to modulating the cellular-driven components of the late-phase physiological response, influencing pathway activity.

Dosage and Administration Information

How to Use Hisaler: Administration Guidelines

The administration of Hisaler (cetirizine hydrochloride) follows specific protocols that define the approved routes, standard dosing, and patient-specific adjustments. The medication is primarily intended for oral intake (via tablets, solutions, or syrups), but an intravenous (IV) form exists for acute, short-term use.

Standard Dosage and Frequency

Population Dose Regimen (Oral) Maximum Daily Dose
Adults (and ge 12 years) 10 mg taken once daily (qDay) 10 mg in 24 hours
Children (6–11 years) 5 mg to 10 mg once daily 10 mg in 24 hours

The standard regimen requires the medication to be administered once every 24 hours. Oral forms can be taken with or without food for convenience. Liquid solutions and syrups must be measured precisely using a designated dosing device, rather than a household teaspoon, to ensure the correct dose is delivered. The IV injectable form, when used for acute administration, is given as a rapid push over a period of one to two minutes.

Population-Specific Adjustments

Specific protocols require modification of the standard dose for patients with impaired renal (kidney) function. In adult patients with moderate to severe renal impairment, the typical oral dose is reduced to 5 mg once daily to prevent accumulation. This adjustment ensures the drug's use aligns with specific patient physiological constraints. If a dose is missed, the next dose should be taken at the next scheduled time; a double dose should not be taken to compensate.

Recent Clinical Evidence

Research evidence / Overview of studies for Hisaler

Evidence for use in Seasonal Allergic Rhinitis (SAR)

Research examining the study of Hisaler in conditions like hay fever relies heavily on Randomized Controlled Trials (RCTs). These studies were used in research exploring how symptoms change over time using treatment arms including inactive substance (placebo) and others. Studies monitored outcomes related to physical discomfort by measuring a Total Symptom Score (TSS), which combines patient-reported scores for issues like sneezing, runny nose, and itchy eyes, as well as outcomes reflecting daily functioning or activity level using Quality of Life questionnaires. These trials included cohorts of Adults, Adolescents, and Children experiencing symptoms during periods of increased symptom activity.

Studies describe patterns observed in the studies over short-term periods, such as a few days to a few weeks, the typical duration of an acute allergy episode. Research highlights data show patterns related to Total Symptom Scores, which varied across the observed patient groups. While the core evidence contributes to the broader evidence landscape, the follow-up durations were limited in many RCTs, with the focus primarily on acute and short-term symptom management as observed in the studies rather than tracking long-term disease patterns over successive seasons.


Evidence for use in Perennial Allergic Rhinitis (PAR)

Hisaler was evaluated in studies involving perennial allergic rhinitis, a condition presenting with cycles of stability and flare-ups that can occur year-round. These studies, including RCTs, focused on conditions where symptoms may vary in intensity over longer timeframes than seasonal allergies. Researchers monitored outcomes related to functional imbalance and patient-reported outcomes describing perceived discomfort over intermediate follow-up periods, commonly lasting several weeks to a few months. The studies explored persistent symptoms such as ongoing nasal discharge, nasal itching, and outcomes reflecting daily functioning or activity level.


What is still uncertain about Hisaler

Despite the high volume of RCT evidence, certain questions and limitations exist in the research base. The follow-up durations were limited in many key RCTs, meaning long-term symptomatic and functional outcomes over many years are not fully characterized by controlled studies. Findings describe group patterns, not personal outcomes, and research provides context but not individual predictions for the severity or duration of symptomatic change.

Key Studies & References

  1. Cetirizine and Levocetirizine Use in Children (Review on clinical trials, safety, and long-term data)
  2. Chronic urticaria: off-label doses of cetirizine (NICE Evidence Summary on Off-label Use, referencing small RCTs)

Frequently Asked Questions (FAQ)

Common questions about Hisaler (FAQ)

Q: How quickly should Hisaler start working?

A: Evidence from controlled studies suggests a rapid onset of activity. The antihistaminic effect was observed to start within 20 minutes for half of the subjects in a controlled setting, and within one hour for most subjects tested after a single 10 mg dose. Individual response and actual onset time may vary.

Q: How long do the effects of Hisaler last?

A: Official regulatory documents state that the medicine is designed to provide relief for a full day. Studies indicate that the antihistaminic effect of a single dose has been documented to persist for up to 24 hours.

Q: Do I need a prescription to get Hisaler?

A: The active ingredient, cetirizine hydrochloride, is widely available in both over-the-counter (OTC) and prescription forms. The status of the specific product, Hisaler, depends on the strength, form, and regulatory classification within a given country.

Q: Can I take Hisaler with coffee or tea?

A: The official product label does not specifically address interactions with caffeine (found in coffee or tea). However, regulatory warnings caution against concurrent use with other substances that act as CNS depressants (meaning they slow down the central nervous system), due to the possibility of additive effects on alertness.

Q: Can Hisaler affect my sleep?

A: Official adverse reaction reports indicate effects on the central nervous system. While somnolence (drowsiness) is commonly reported, the opposite effect, insomnia (difficulty sleeping), has also been listed as a side effect in post-marketing surveillance reports.

Q: Can Hisaler be used if I am taking supplements?

A: Official sources describe the need for consultation regarding mixing the medicine with herbal supplements and other complementary medicines. This guidance is especially relevant for supplements that may already cause side effects similar to the medicine, such as drowsiness or dry mouth.

Q: What does Hisaler's label say about driving?

A: The official label provides a clear warning regarding activities requiring mental alertness. Due to the reported occurrence of somnolence (drowsiness) or dizziness, the label states that users should exercise due caution when operating potentially dangerous machinery or driving a car.

Q: Does Hisaler have any effect on blood pressure?

A: The official adverse reaction list for the medicine includes cardiovascular effects. The less common side effects reported in official documents include tachycardia (increased heart rate) and hypertension (high blood pressure).

Q: Is there a generic version of Hisaler available?

A: The active ingredient in this medication is Cetirizine Hydrochloride, which is widely available as a generic drug product, according to regulatory status listings.

Q: Where can I find the official regulatory information about Hisaler?

A: Official, authoritative information about the medicine's regulatory profile, label, and safety details is publicly available. This information is made publicly available by various governmental health agencies, including the FDA (DailyMed), the European Medicines Agency (EMA), and the NIH (MedlinePlus).

Q: Does Hisaler have any known interactions with herbal products?

A: Official regulatory sources advise users to exercise caution with herbal remedies and supplements. This is primarily a concern when the herbal product may cause effects similar to the medicine, such as increased sleepiness or dry mouth.

Q: Is Hisaler suitable for older adults?

A: Official product information confirms that Hisaler is generally suitable for adults, but special considerations exist for the geriatric population. For older patients, such as those 77 years and older, an adjustment to the usual daily amount is often officially recommended. This helps account for the potential for increased sensitivity and natural decreases in drug clearance.

Q: What is the difference between Hisaler and [Commonly Known Drug Name]?

A: Official literature describes Hisaler as a second-generation H1 receptor antagonist that is designed to act mainly on the peripheral tissues of the body. Its selective pharmacological profile, associated with minimal central nervous system ( CNS) activity, is a key characteristic that is used to differentiate it from other types of antihistamines.

Q: Is Hisaler considered a long-term treatment?

A: While the initial clinical trials focused on short-term symptom relief, regulatory information provides context on its use duration by acknowledging that patients may take it over long-term daily use periods (such as a few months to years). This context is provided in safety warnings regarding the potential for severe itching (pruritus) that may occur when the medicine is stopped after extended use.

Q: Are there any foods or drinks that should be avoided when using Hisaler?

A: According to the official label, taking the medicine with food does not change the total amount of medicine absorbed into the body. However, food has been documented to cause a slight delay in the time it takes for the medicine to reach its maximum concentration.

Q: Why do some people say Hisaler didn't work for them?

A: Official clinical trial data show that patient responses to the medicine vary between patient groups. Research studies primarily provide data based on average group patterns and are not designed to offer individual predictions regarding treatment outcomes.

Q: Can I stop using Hisaler if I start feeling better?

A: Official safety warnings mention the potential for severe itching (pruritus) that has been reported to occur when the medicine is stopped, particularly after long-term use. Official safety warnings describe that in reported cases, the symptom sometimes improved after the medicine was restarted or a tapering (gradual reduction) regimen was implemented.

Q: Is Hisaler a cure for the condition it treats?

A: Official documents confirm that the medicine is approved for the relief of symptoms caused by allergic conditions. It functions by blocking the effects of the body's natural allergic chemical, histamine. It is officially approved for the relief and management of symptoms.

Q: Can Hisaler affect the results of lab tests?

A: Official prescribing information states that the medicine can inhibit the reaction of the skin to histamine, which may interfere with testing procedures. Therefore, discontinuation for a specific period (often 3 to 10 days) is required before patients undergo allergy skin prick tests to ensure accurate results.

Q: Why do doctors prescribe Hisaler instead of other options?

A: The medicine is classified as a mathbfselective peripheral H1 receptor antagonist. Its mechanism of action, which involves minimal central nervous system ( CNS) activity, is a key characteristic that distinguishes its use profile from older-generation agents.

Q: Can Hisaler be used by people with a history of liver problems?

A: For individuals with a history of liver issues, regulatory information provides specific guidance. For patients with moderate or severe hepatic (liver) impairment, an official reduced starting amount is utilized to ensure the drug's use is aligned with the patient's physiological constraints.

Q: Why is Hisaler not allowed for people with [Specific Contraindication]?

A: The medicine is contraindicated in cases of severe renal (kidney) impairment because the body's ability to clear the drug is significantly decreased in these patients. This reduction in clearance can lead to drug accumulation and increased systemic exposure, which is the documented basis for its contraindication in this condition.

Q: Does Hisaler contain any common allergens?

A: Official labels warn that the medicine is contraindicated for individuals with a known hypersensitivity to the active ingredient, related compounds, or any of the non-active ingredients, known as excipients. While excipients vary by manufacturer, the label warns that the medicine is contraindicated for individuals with a known hypersensitivity to the active ingredient, related compounds, or any of the excipients (non-active ingredients).

Q: Is Hisaler meant to be taken regularly or only when needed?

A: For approved uses like Seasonal and Perennial Allergic Rhinitis, the official label describes the medicine as a daily treatment (once daily). The description of a daily treatment is aligned with maintaining consistent symptom control over time.

How should Hisaler be stored and disposed of?

How to Store and Dispose of Hisaler?

Hisaler (Cetirizine Hydrochloride) must be stored at Controlled Room Temperature, between 20^circ to 25^circC (68^circ to 77^circF), and should not be stored above 25^circC. The medicine must be kept in its tightly closed container, protected from excess heat and moisture, and kept out of the sight and reach of children.

Stability and Disposal

The Oral Solution form must be used within 6 months after opening. Do not use any form of the medicine after the expiry date.

For disposal, Hisaler should not be thrown into wastewater or household waste. Consult a pharmacist or utilize an official drug take-back program for proper disposal, which helps protect the environment.

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

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