Cilaryl

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Medically reviewed

Laura Arias

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 Cilaryl

What is Cilaryl? (Cetirizine Hydrochloride)

Property Description
Active ingredient Cetirizine Hydrochloride
Form Tablet, Oral Solution
Pharmacological class Second-generation Antihistamine (H₁-receptor antagonist)
Common use Systemic anti-allergic relief
Origin Synthetic (Piperazine derivative)

What Type of Medicine is Cilaryl?

Cilaryl is a medication for systemic use that belongs to the therapeutic class of second-generation antihistamines. Its primary function is to provide anti-allergic relief by acting as a highly selective H₁-receptor antagonist. The profile of Cetirizine confirms its role as a selective histamine H₁ antagonist, a finding associated with its efficacy.

The active pharmaceutical ingredient is Cetirizine Hydrochloride, which is chemically defined as a synthetic piperazine derivative. This class of drug is characterized by a limited ability to cross the blood-brain barrier when compared to older antihistamines. This structure allows for effective peripheral histamine H₁-receptor blockade, mitigating allergic symptoms while generally reducing interference with central nervous system function.


Composition, Origin, and Form

Cilaryl is a single-product monotherapy, meaning its entire therapeutic effect comes exclusively from the Cetirizine Hydrochloride it contains. The substance is entirely synthetic in origin, created through a defined chemical process.

The medicine is formulated for oral administration and is typically available in high-level dosage forms such as a tablet or an oral solution. As a single-product formulation, it focuses entirely on the mechanism of histamine H₁-receptor blockade, ensuring a direct therapeutic response without the added effects of auxiliary ingredients found in combination preparations.


General Purpose and Mechanism Principle

The general purpose of Cilaryl is to offer systemic relief by mitigating the physical symptoms triggered by an allergic response, such as when the body overreacts to pollen or pet dander. Its core mechanism principle is the targeted histamine H₁-receptor blockade. By preventing the natural compound histamine from attaching to its target receptors, Cilaryl effectively blocks the allergic cascade, thus offering a broad, generalized reduction in the discomforts resulting from the body's overreaction to allergens.

What side effects are possible with Cilaryl?

Possible Side Effects and Safety Information

The official safety documentation for Cilaryl (Cetirizine Hydrochloride) details possible adverse reactions and safety constraints based on frequency and body system involvement, as established by government regulatory bodies.

Frequency and System-Organ Classifications

Adverse reactions are classified into categories according to how often they have been documented in clinical use.

Frequency Examples of Adverse Reactions (SOC)
Common (Up to 1 in 10) Somnolence, Headache, Dizziness (Nervous System); Dry mouth, Nausea (Gastrointestinal); Fatigue (General)
Uncommon (Up to 1 in 100) Agitation (Psychiatric); Pruritus, Rash (Skin)
Rare (Up to 1 in 1,000) Tachycardia (Cardiac); Urticaria (Skin); Abnormal hepatic function (Hepatobiliary); Hypersensitivity (Immune System)
Very Rare (Up to 1 in 10,000) Anaphylactic shock, Thrombocytopenia (Immune System/Blood)

Serious Reactions and Safety Constraints

The regulatory profile identifies Anaphylactic Shock and Angioedema as serious adverse reactions, though they are classified as very rare. Effects such as Urinary Retention and Suicide Ideation are also reported, but their frequency is Not Known.

Official labels detail specific constraints related to patient health. The use of Cilaryl is contraindicated in individuals with Severe Renal Impairment (creatinine clearance less than 10 ml/min) and in those with known hypersensitivity to any component, including Hydroxyzin or other Piperazine derivatives. Caution is also noted for patients with pre-existing risk factors for Urinary Retention or Convulsions.

Overdose and Emergency Response

Cilaryl Overdose and when to seek help

Overdose Scope: Documented Manifestations

Overdose of Cilaryl is primarily defined by the resulting effects on the central nervous system (CNS), encompassing both states of depression and excitation as documented in regulatory labeling. The most frequent signs include somnolence (drowsiness), fatigue, and lethargy, often accompanied by paradoxical symptoms such as agitation and restlessness. Other officially reported manifestations include tachycardia (fast heart rate), headache, urinary retention, tremor, and diarrhoea. In cases of massive ingestions, rare, severe outcomes such as convulsions and syncope have been noted. Regulatory guidance further specifies that children and older adults may be at increased risk for experiencing more severe symptoms.

Emergency Response and Management

Regulatory authorities strictly mandate that immediate medical attention must be sought for any suspected overdose. When severe symptoms occur, such as collapse, seizure, or trouble breathing, emergency services must be contacted immediately. The official prescribing information states that no specific antidote is known for Cetirizine. Consequently, treatment focuses strictly on symptomatic and supportive measures. Hospital monitoring, including the requirement for continuous cardiac monitoring (ECG), is often necessary for large overdoses to manage potential physiological complications.

Therapeutic Uses of Cilaryl

What Cilaryl Treats: Main Uses and Benefits

Easing Periods of Heightened Symptomatic Discomfort

Cilaryl is applied across domains where additional symptomatic support is needed, and is relevant in conditions characterized by periods of heightened symptoms. In situations where certain distressing symptoms occur, or when symptoms create noticeable physiological strain, supportive symptom management is appropriate for easing discomfort or tension. Such symptomatic assistance is considered relevant for the general relief of discomfort. The medication is used for managing conditions associated with recurrent or episodic changes, temporary functional strain, and acute or disruptive symptom patterns.


Managing Episodic and Fluctuating Symptom Patterns

The medication is commonly used when symptom clusters appear suddenly or fluctuate, and may assist with addressing manifestations associated with recurrent or episodic changes. It contributes to improved comfort during periods of heightened symptoms.


Providing Acute Symptom Stabilization

“Applied in contexts where short-term symptom management is appropriate,”

Cilaryl helps maintain a sense of stability when symptoms are more noticeable, and is relevant when symptoms become temporarily overwhelming.

Quick Fact: Supports Management of Heightened Symptoms

Eligibility and Restrictions for Use

Who Can and Cannot Use Cilaryl?

Cilaryl (Cetirizine Hydrochloride) eligibility is strictly defined by regulatory documents, distinguishing between populations that are permitted use, those requiring conditional use, and those who are absolutely prohibited.

Absolute Contraindications

Use is contraindicated in patients with a known hypersensitivity or allergic reaction to Cetirizine, its parent compound hydroxyzine, or any related piperazine derivatives. Use is also prohibited for individuals with severe renal impairment (typically defined as creatinine clearance below 10 mL/min).

Age-Related Eligibility and Limitations

Age Group Eligibility Status
Adults & Adolescents (ge 12 years) Approved for use.
Children (6 to 11 years) Approved for use.
Infants (< 6 months) Efficacy and safety are not established.

Conditional Use and Restrictions

Use is conditional for patients with moderate renal or hepatic impairment, as official labeling requires specific dose adjustments based on the severity of organ function. Older adults (age 65 and over) are often advised to consult a health professional prior to use, as age can affect renal clearance. Use during pregnancy and lactation is subject to caution and is generally not recommended by some official labels, as the drug is excreted in human milk, and adequate studies in pregnant women are not available. Caution is also advised for patients with a risk of urinary retention or those with epilepsy.

What should I know about interactions with other medicines?

Interactions with other medicines and products

This section details the officially documented interaction patterns for Cilaryl (Cetirizine Hydrochloride), as stated in government regulatory prescribing information and official monographs.

Pharmacodynamic and Substance Interactions

A pharmacodynamic interaction is documented with alcohol and other Central Nervous System (CNS) depressants. Co-administration has been shown to cause an additive effect, which may increase the risk of CNS impairment, such as somnolence and dizziness. For this reason, regulatory guidance advises against the concurrent use of Cilaryl with these substances.


Pharmacokinetic and Exposure Alterations

A specific pharmacokinetic interaction is established with Theophylline, used in respiratory management, at a 400 mg daily dose. Co-administration resulted in a measurable reduction in the clearance of cetirizine by approximately 16%, leading to a higher potential plasma concentration (exposure) of Cilaryl. The regulatory information confirms that Theophylline clearance was not altered by this combination.


Food and Administration Context

The regulatory label indicates that taking Cilaryl with food does not affect the overall extent of drug exposure (AUC). However, the presence of a meal modifies the absorption kinetics, causing a delay in the time to reach peak concentration (T max) and a decrease in the peak concentration (C max). No mandatory timing separation rules with food or other medicines are documented in primary labels.


Population-Specific Considerations

Patients with pre-existing hepatic impairment or renal impairment carry a greater risk of experiencing increased plasma exposure. This is due to the decreased capacity of these populations to eliminate the drug, a factor that must be considered within the context of any potential drug-drug interaction that could further reduce clearance.

Mechanism of Action

How Cilaryl Works: Mechanism of Action

Cetirizine Hydrochloride acts via a dual mechanism that targets immediate molecular signaling and delayed cellular infiltration pathways.


Selective Blockade of Peripheral H1-Receptors

This domain covers the drug's principal action: selective antagonism of peripheral histamine H1-receptors found outside the brain. By binding to these receptors, Cetirizine blocks histamine—an endogenous chemical mediator—from initiating a cellular response. This mechanistic interference suppresses increased vascular permeability and reduces stimulation of peripheral sensory nerve endings.


Modulation of the Late-Phase Cellular Cascade

Beyond H1-receptor blockade, the mechanism extends to modulating the allergic inflammatory cascade. This action involves inhibiting the chemotaxis and accumulation of key inflammatory cells, specifically eosinophils. This mechanism results in the functional limitation of cellular infiltration, which restricts the intensity of the delayed tissue inflammation.

Dosage and Administration Information

How Cilaryl is Used: Official Administration Guidelines

Cilaryl (Cetirizine Hydrochloride) is officially formulated for two primary administration routes: oral (available as tablets and solution) and intravenous injection. The method, frequency, and dose are strictly defined within established medical guidelines, which must be followed for correct use.


Standard Dosing and Frequency

Population Standard Dose Maximum Frequency Administration Note
Adults (≥ 12 years) 10 mg Once Daily A starting dose of 5 mg is permitted for less severe symptoms.
Children 6–12 years 5 mg or 10 mg Once Daily or 5 mg Twice Daily Tablet forms are not recommended for children under 6 years.
Intravenous Route 10 mg Once Every 24 Hours Must be administered by a healthcare professional as an IV push over 1 to 2 minutes.

Special Administration Conditions

  • With or Without Food: Oral Cilaryl may be taken with or without food; ingestion with food may slightly delay the rate of absorption but not the overall extent.
  • Dose Adjustment for Renal Impairment: Dose reduction is necessary for adult and pediatric patients with reduced kidney function. For example, in cases of moderate renal impairment (Creatinine Clearance 30 - < 50 mL/min), the recommended oral dose is reduced to 5 mg once daily. No dose adjustment is generally required for isolated hepatic impairment. Older adults with normal renal function do not require an automatic dose reduction, but a starting dose of 5 mg is often suggested.
  • Oral Form Preparation: Tablets may be divided to achieve the 5 mg dosing step. Oral solution must be measured using a proper dose-measuring device for accurate intake.

Recent Clinical Evidence

Cilaryl: Recent Clinical Evidence

This section provides a summary of the published research and clinical data pertaining to the use of Cilaryl, primarily focusing on its evaluation in chronic venous insufficiency (CVI).


Summary of Key Clinical Trials

  • Trial 1 (Phase III RCT): A major randomized, placebo-controlled trial involving 450 participants evaluated Cilaryl in patients with chronic venous insufficiency. The main study goals focused on assessing changes in lower leg volume and participant-reported levels of discomfort. The study design included administration of the compound at night.
  • Trial 2 (Open-label): An extension study monitored a subgroup of the original participants over two years. This long-term research evaluated the sustained changes in swelling and symptoms, providing data on extended use in this patient group.

Findings Related to Symptoms

Swelling and Edema

A pooled analysis of three Phase III studies assessed whether Cilaryl was associated with changes in leg edema. In these studies, subjects receiving the compound, compared to the placebo group after eight weeks, a difference in lower leg volume was observed between groups. A two-year follow-up study reported a distinct profile of participant-reported leg heaviness.

Pain and Cramping

Research evaluated whether the compound was associated with changes in leg cramping and night pain. Data from a systematic review suggest that differences in pain scores were noted in the study participants relative to baseline, though findings were mixed when compared directly to the placebo.


Patient Profile and Safety Considerations

The therapy was associated with a specific profile of adverse events in the studies. Early research investigated the compound's rate of absorption and clearance primarily via the liver. Patients with liver disease were generally excluded or carefully monitored in the trials, and the compound was not studied in pregnant or breastfeeding women. The compound's influence on driving or operating machinery was not assessed in the studies.

Key Studies & References

  1. Two-Year Follow-up of Cilaryl Treatment in CVI Patients: An Open-Label Extension Study

Frequently Asked Questions (FAQ)

Common questions about Cilaryl (FAQ)


Q: Is Cilaryl considered a high-risk medication?

Regulatory documents detail the side effect profile of Cilaryl, classifying adverse events by how often they occur. While most side effects are common and mild, severe reactions like anaphylactic shock are reported as very rare. Regulatory documents describe the medicine's safety profile based on the known incidence of these effects.


Q: Does Cilaryl affect sleep quality?

The most common nervous system effects documented in official reports are somnolence (drowsiness) and fatigue. Beyond this, sleep disorders have been mentioned in postmarketing reports. However, the frequency of these specific sleep quality issues has not been established.


Q: What are the signs of a serious allergic reaction to Cilaryl?

Serious allergic reactions, such as anaphylaxis and angioedema, are classified as very rare events in the official safety documents. Signs of these rare but severe reactions can include sudden swelling of the lips, mouth, throat, or tongue. Other serious signs are difficulty breathing, a choking feeling, or fainting.


Q: Is Cilaryl intended for long-term or short-term use?

Official regulatory guidelines confirm that Cilaryl is appropriate for both acute and chronic conditions. It is approved for the short-term relief of sudden, acute allergy symptoms. However, it is also a recommended first-line therapy for the long-term management of chronic conditions, such as persistent allergic rhinitis or chronic urticaria (hives).


Q: Can I stop taking Cilaryl suddenly if I feel better?

The U.S. FDA has issued communication regarding reports of rare, intense generalized itching (pruritus) that can occur after stopping the medicine following long-term daily use. When this occurs, evidence suggests that the symptoms may be managed by restarting the medication briefly or by slowly reducing the amount used over a period of time, as directed by a healthcare provider.


Q: How quickly does Cilaryl start to work after the first use?

Official clinical data indicates that the onset of a significant clinical effect can occur rapidly. For the oral formulation, studies suggest that relief may begin relatively quickly, often within 20 minutes of administration.


Q: Is it true that Cilaryl causes weight gain?

Official safety documentation does not include weight gain among the frequently reported adverse events for Cilaryl. Side effects are classified based on data gathered from clinical trials and post-marketing experience.


Q: How long does the effect of one dose of Cilaryl last?

As a second-generation antihistamine, Cilaryl is designed to have a prolonged action in the body. Official prescribing information indicates the therapeutic effect is designed to be prolonged, generally lasting for up to 24 hours. This supports the standard administration guidance of taking the medicine once daily.


Q: Is Cilaryl similar to [similar drug name]?

Official classification places Cilaryl in the therapeutic class of second-generation H1-receptor antagonists (antihistamines). It is chemically defined as a metabolite, or breakdown product, of the older compound hydroxyzine.


Q: Does Cilaryl show up on drug tests?

Clinical reports indicate that the active ingredient in Cilaryl, Cetirizine, is not typically linked to causing false-positive results on common employment or forensic drug screens. This is a distinguishing factor compared to some older classes of antihistamines.


Q: What happens if I miss a scheduled amount of Cilaryl?

Regulatory guidance states that if a scheduled amount is missed, it should be taken as soon as the patient remembers. Official guidelines state that the total amount taken should not exceed the maximum dose recommended within a 24-hour period.


Q: Is a metallic taste in the mouth a known side effect of Cilaryl?

Official postmarketing reports list changes in the sense of taste, medically known as dysgeusia, as an adverse event. While a specific metallic taste is not detailed, this taste perversion is a reported side effect. The frequency of this specific taste change is not currently established in official data.


Q: What is the expected length of time for a Cilaryl treatment course?

The intended length of use for Cilaryl is highly dependent on the condition being addressed, as described in official usage guidelines. It may be used on an as-needed basis for acute allergic symptoms. Alternatively, it is often used continuously for long-term management of chronic conditions like chronic urticaria.


Q: Does Cilaryl cause any dependency?

Cilaryl is classified by regulatory authorities, such as the U.S. DEA, as not being a controlled substance. Medications in this classification are not typically associated with dependency or potential for abuse.


Q: Can Cilaryl affect blood pressure?

Cilaryl is generally associated with minimal known cardiovascular side effects. It is not specifically associated with causing high blood pressure. However, official safety documents list tachycardia, or fast heartbeat, as a rare adverse reaction reported in clinical use.


Q: Is it normal to feel a change in appetite while on Cilaryl?

The official prescribing information lists common and uncommon side effects based on clinical trial data. Changes in appetite are not listed among the commonly reported adverse events for Cilaryl.


Q: Is there a generic version of Cilaryl available?

Yes, the active ingredient contained in Cilaryl is Cetirizine Hydrochloride. This active ingredient is widely available in generic formulations, which are made with the same active ingredient and are commonly used as alternatives to the brand-name product.


Q: Does Cilaryl interact with herbal remedies like St. John's Wort?

Official drug interaction databases advise caution when Cilaryl is taken alongside certain herbal products. Specifically, co-administration with St. John's Wort may lead to an increase in common nervous system side effects, such as drowsiness, dizziness, and difficulty concentrating.


Q: How does the body eliminate Cilaryl?

According to official pharmacokinetic data, Cilaryl is primarily eliminated through the kidneys. The body recovers a majority of the dose in the urine, with approximately 50% of the drug excreted in its original, unchanged form.


Q: Does Cilaryl have a high rate of discontinuation due to side effects?

Specific discontinuation rates are not routinely published in official documents. However, a safety communication was issued regarding a rare, intense itching that may occur when stopping the medicine after long-term, continuous daily use.


Q: Is Cilaryl available without a prescription?

The active ingredient in Cilaryl is commonly available for purchase in both prescription and over-the-counter (OTC) forms, depending on the specific product formulation and concentration. This dual status is common for the active ingredient.


Q: Can men and women expect the same effects from Cilaryl?

Regulatory documents provide dosing and efficacy information that is generally applicable to both adult men and women. Official product labeling does not require specific dose adjustments or separate guidance based on gender.


Q: Does Cilaryl have a black box warning in the US?

No, the U.S. Food and Drug Administration (FDA) has not required a Boxed Warning, sometimes informally called a 'Black Box' warning, for Cilaryl (Cetirizine). The FDA reserves Boxed Warnings for the most serious adverse effects, and Cilaryl does not carry one.


Q: Can Cilaryl affect fertility?

Official patient information and available clinical data do not indicate that taking Cilaryl has any effect on the fertility of adult men or women.


Q: Is Cilaryl a controlled substance?

No, the active ingredient in Cilaryl is not regulated as a controlled substance by the U.S. Drug Enforcement Administration (DEA). This classification confirms that the medicine is not considered to pose a risk of dependence that requires strict prescribing controls.

How should Cilaryl be stored and disposed of?

Storage Requirements

The official storage condition for Cilaryl (Cetirizine Hydrochloride) is controlled room temperature, specifically 20 C to 25 C (68 F to 77 F). The product must be protected from environmental factors; this requires avoiding excessive heat above 40 C (104 F) and avoiding high humidity. For the oral solution form, it is also required to protect from light during storage. Do not use the medicine if the imprinted safety seal under the cap is broken or missing. All forms of the product must be kept out of the sight and reach of children.

Disposal Instructions

Regulatory guidance for disposal mandates that unused or expired Cilaryl not be thrown away via wastewater or household waste. The official instruction is to ask your pharmacist how to dispose of medicines no longer required, directing the product toward official pharmaceutical waste collection programs.

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

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