Alcet

Quick links to important sections

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

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

Overview of Alcet

Quick Facts

Property Description
Active ingredient Levocetirizine Dihydrochloride
Form Oral Tablet, Oral Solution
Pharmacological class Second-Generation Antihistamine
Common use Relief from general allergic symptoms
Origin Synthetic, Single Isomer

What Type of Medicine is Alcet? Defining the Antihistamine Class

Alcet is a trade name for a synthetic medicinal preparation defined by its active ingredient, Levocetirizine Dihydrochloride. It belongs to the high-level pharmacological class of antihistamines and is officially categorized as a second-generation H₁-receptor antagonist.

This designation establishes that the medication operates by performing selective antagonism of the peripheral H₁ receptors to block the effects of histamine, a key chemical released during allergic reactions. The classification of Levocetirizine as a second-generation compound is characterized by a lower potential for sedation compared to older antihistamines. This characteristic allows it to provide relief from allergic manifestations while minimizing effects on daily cognitive function.

Composition and Origin: Levocetirizine as a Single Isomer

The foundational active substance is Levocetirizine, a highly purified, single-isomer compound that is chemically defined as the active R-enantiomer of the drug Cetirizine. This precise chemical isolation distinguishes it from a racemic mixture, reflecting its origin as a derivative belonging to the Piperazine derivative chemical group. Alcet is commonly marketed as both a solid film-coated tablet and a liquid oral solution, with the solution often positioned to cater specifically to the target patient group of children and those who have difficulty swallowing pills. Both dosage forms utilize the same active ingredient, Levocetirizine Dihydrochloride, for the oral route of administration.

What side effects are possible with Alcet?

Possible Side Effects and Safety Information

The safety profile of Alcet (Levocetirizine Dihydrochloride) is characterized by classifying adverse reactions according to their frequency and the physiological system affected, as documented in official regulatory labeling.

Frequency-Classified Adverse Reactions

Adverse reactions are formally categorized based on the likelihood of their occurrence:

  • Common (ge 1/100 to < 1/10): Systemic effects frequently listed in regulatory documents include somnolence, fatigue, and headache. Dry mouth and nasopharyngitis are also often classified as common.
  • Uncommon (ge 1/1,000 to < 1/100): Effects such as asthenia (loss of strength) and abdominal pain are noted in this category.
  • Not Known (Post-Marketing): Reactions identified after broad use, where frequency is not precisely estimated, include aggression, hallucination, depression, and convulsion.

System-Organ-Class Groupings and Serious Reactions

Side effects are grouped into system-organ classes, with effects noted in the Nervous System Disorders (e.g., somnolence) and Gastrointestinal Disorders (e.g., dry mouth). Post-marketing surveillance has also documented cases of significant reactions within the Immune System Disorders, ranging from generalized hypersensitivity to anaphylaxis.

Serious Adverse Reactions highlighted in official labeling include urinary retention. A rare risk of moderate to severe pruritus (itching) has been observed after discontinuation following long-term daily use.


Population-Specific Safety Constraints

Official labeling defines specific constraints for certain patient groups. The medication is contraindicated in individuals with end-stage renal disease (Creatinine Clearance < 10 mL/min), and dose adjustment is required for all other degrees of renal impairment. Caution is advised for older adults due to the higher likelihood of reduced renal function. Furthermore, use with alcohol or CNS depressants should be avoided due to the potential for additive impairment of alertness.

Overdose and Emergency Response

The official regulatory documentation for Alcet (levocetirizine dihydrochloride) overdose strictly defines the expected clinical manifestations, differentiating the presentation based on age. In adults, the most common documented sign of overdose is pronounced drowsiness (somnolence, sedation). In contrast, pediatric patients typically exhibit an initial phase of agitation and restlessness, which is then followed by the onset of drowsiness. Regulatory authorities have documented severe outcomes, including significant CNS depression such as stupor, and cardiac effects like tachycardia, particularly following intake of at least five times the recommended daily dose. Other reported manifestations include confusion, dizziness, and urinary retention. In the event of an overdose, labeling mandates that individuals seek emergency medical attention immediately and call a Poison Control Center without delay. Management is limited to symptomatic and supportive treatment, as the prescribing information confirms that no specific antidote is known to exist. The drug is not effectively removed by dialysis, though supportive procedures like gastric lavage may be considered after a recent, acute ingestion.

Therapeutic Uses of Alcet

What Alcet Treats: Main Uses and Benefits

Alcet supports symptomatic relief across the main clinical presentations of allergies, helping patients manage discomfort and maintain daily functioning. It is commonly used for easing symptoms associated with allergic rhinitis (seasonal and perennial) and chronic skin manifestations, specifically chronic idiopathic urticaria.


Symptomatic Relief for Allergic Rhinitis

The medication is applied across therapeutic domains involving acute or disruptive symptom patterns characteristic of allergic rhinitis. Alcet helps address symptom clusters that may become intense or disruptive. This is relevant for managing symptoms that interfere with daily comfort, such as persistent sneezing, a runny nose (rhinorrhea), and nasal itching. It also addresses symptoms related to eye irritation, such as watery, itchy, and red eyes.

“Alcet may be part of symptomatic management when acute manifestations of allergic rhinitis or chronic urticaria interfere with functional stability.”


Management of Chronic Allergic Skin Manifestations

Alcet is also considered relevant in conditions characterized by periods of heightened symptoms, specifically the uncomplicated skin manifestations of chronic idiopathic urticaria. In this context, the medication assists with maintaining functional stability by managing symptoms that create noticeable physiological strain, such as chronic pruritus (skin itching), and is used for managing the presence of wheals. This provides support that helps ease the overall symptom burden associated with persistent skin irritation.


Quick Fact: Relief for Allergic Discomfort
Primary Focus Symptoms related to inflammatory or irritative states
Key Domains Allergic rhinitis and chronic urticaria
Core Benefit Contributes to improved comfort during symptomatic periods

Eligibility and Restrictions for Use

The eligibility profile for Alcet (levocetirizine dihydrochloride) is strictly governed by regulatory status concerning chemical intolerance, renal function, and age. This information defines who is officially permitted to use the medicine and who is prohibited.

Populations Who Must Not Use Alcet (Contraindicated)

The medicine is strictly prohibited for patients with a known history of hypersensitivity to levocetirizine, cetirizine, hydroxyzine, or any other piperazine derivative. Use is also contraindicated in patients with end-stage renal disease (creatinine clearance CL CR, < 10 mL/min), including those undergoing hemodialysis. A specific contraindication applies to pediatric patients 6 months to 11 years of age with any degree of impaired renal function.

Restrictions and Special Considerations

Use is established for adults and children ge 6 months of age, though the tablet formulation is generally not recommended for children under 6 years. Use in infants younger than 6 months is not established. For patients ge 12 years with mild to severe renal impairment, use is restricted and requires specific adjustments based on CL CR. No adjustment is needed for solely hepatic impairment. The medicine is not recommended for use in breastfeeding/lactating women. Caution is required for individuals with predisposing factors for urinary retention.

What should I know about interactions with other medicines?

Interactions with other medicines and products

This section describes the officially documented interaction patterns for Alcet (Levocetirizine Dihydrochloride), based strictly on government regulatory labeling. No drug-drug combination is formally classified as a contraindication based solely on an interaction mechanism.

Property Official Regulatory Statement
Medicinal product categories with documented interactions Central Nervous System (CNS) Depressants
Specific interacting medicines (if explicitly listed) Ritonavir and Theophylline (documented via the racemate, cetirizine)
Mechanistic basis of interactions (only if stated in label) Pharmacodynamic (Additive CNS Depression) and Pharmacokinetic (Clearance Modulation)
Timing-based interaction rules (if applicable) Food decreases the rate of absorption (Tmax) but does not reduce the total extent of absorption (AUC).
Population-specific interaction notes (if applicable) Risk of adverse reactions may be greater in patients with impaired renal function due to the drug’s substantial kidney excretion.
Interaction-related restrictions Concurrent use of alcohol or other central nervous system depressants must be avoided.

Interaction severity classification (as defined in official documents): Interactions with alcohol and other CNS depressants are classified as Use with Caution, based on the regulatory requirement to avoid co-administration due to the potential for additive impairment of central nervous system performance.

Resulting interaction structure The regulatory interaction profile is primarily defined by a mandatory restriction against co-administration with CNS depressants, driven by a pharmacodynamic additive effect. Pharmacokinetic data established that co-administration with agents like Ritonavir and high-dose Theophylline modulates the drug's clearance and total exposure. Regulatory documents confirm that while food delays the absorption rate, the overall drug exposure remains unaltered.

Mechanism of Action

Molecular Lock on the Histamine H1 Receptor

The mechanism of Alcet is centered on its action as a high-affinity inverse agonist at the peripheral Histamine H1 Receptor. This molecular interaction stabilizes the receptor in an inactive state, effectively preventing the binding of endogenous histamine and suppressing the H1-mediated signal transduction cascade. This immediate receptor blockade establishes the cessation of downstream signaling that drives acute physiological responses mediated by histamine.


Regulation of Vascular Permeability and Sensory Nerve Signaling

The downstream consequence of H1 inverse agonism is the stabilization of two key systems. First, it inhibits histamine-driven changes in the vascular endothelium, thereby restricting capillary leakage and subsequent tissue fluid accumulation. Second, the drug suppresses the signaling of peripheral sensory nerve endings that transmit the sensation of itching. This dual action contributes to the rapid functional suppression of histamine-mediated physiological responses.


Selective Peripheral Activity and Anti-Inflammatory Modulation

Alcet exhibits high peripheral selectivity due to its minimal ability to cross the blood-brain barrier, concentrating its action where the physiological response occurs. Furthermore, the molecule supports the modulation of the secondary, late-phase response by inhibiting the functional activity and recruitment of key inflammatory cells, such as eosinophils, thereby contributing to the attenuation of the secondary, cellular inflammatory cascade.

Dosage and Administration Information

How to Use Alcet

Alcet (levocetirizine dihydrochloride) is used according to specific high-level administration guidelines. This section describes the standard oral administration regimen, frequency, and population-specific dose adjustments.

Standard Administration Scope

Field Instruction Summary
Route of administration The only approved method is oral administration.
Dosing schedule The standard maintenance dose for adults and adolescents (12 years and older) is 5 mg once daily. The maximum dose should not exceed 5 mg per 24 hours.
Timing in relation to food The medicine can be taken with or without food.
Frequency and Timing The full daily dose is taken as a single intake, preferably in the evening.
Missed-dose rules If a dose is missed, individuals should resume the schedule with the next dose at the usual time; a double dose should not be taken.

Population-Specific Use Rules

Dose adjustments are implemented based on age and kidney function, as levocetirizine is primarily eliminated through the kidneys.

  • Children (6–11 years): The maximum daily dose is 2.5 mg once daily.
  • Children (6 months–5 years): The maximum daily dose is 1.25 mg once daily, typically administered using the oral solution.
  • Renal Impairment: For adults with reduced kidney function, the dose must be formally adjusted or the interval between doses must be extended based on the measured Creatinine Clearance (CLCR). No adjustment is required solely for hepatic (liver) impairment.

This structure defines the standardized protocol for Alcet, setting clear parameters for dose, frequency, and administration modifications without reference to therapeutic claims or safety concerns.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Alcet


Evidence for Use in Allergic Rhinitis (Seasonal and Perennial)

Research exploring how symptoms change over time in patients with allergic rhinitis includes short-term, placebo-controlled trials, many of which were applied in studies examining patient-reported experiences in adults and adolescents (12 years and older) with moderate to severe allergic rhinitis. Researchers evaluated patient-reported outcomes, such as the Total Nasal Symptom Score (TNSS) and the Total Ocular Symptom Score (TOSS), alongside measures of functional impact like Quality of Life (QoL). Studies monitored the evolution of these outcomes across defined time intervals, typically lasting between two and six weeks.

The findings describe patterns observed in the studies related to episodes where symptoms become more noticeable. For perennial allergic rhinitis, which involves persistent symptoms, studies also explored continuous observation over periods extending up to six months. Research describes short-term changes in these outcomes, and data show patterns related to how symptoms evolved in the observed populations.

Evidence for Use in Chronic Idiopathic Urticaria

Alcet was evaluated in research settings involving Chronic Idiopathic Urticaria (CIU), which is a condition characterized by fluctuating or episodic manifestations of hives. These studies mainly consisted of short-term, double-blind, placebo-controlled trials in adults and adolescents. Research focused on outcomes capturing phases of heightened symptom activity, particularly the intensity of chronic pruritus (itching) and the presence of wheals (hives). Studies reported how symptoms evolved in the observed populations, with the key outcomes linked to inflammatory or irritative states.


Areas of Uncertainty and Remaining Research Gaps

Long-term effects are not fully established regarding the full characterization of use beyond six months. The follow-up durations for many controlled trials were limited. Comparative evidence is lacking for head-to-head trials against all other contemporary allergy medications. Data for certain groups remain insufficient; for instance, scientific research reports that there is limited information from controlled studies available for children under 6 years of age. Research provides context but not individual predictions, and for certain populations, particularly the very young, research is ongoing and indicate a continuing need for additional study.

Frequently Asked Questions (FAQ)

Common questions about Alcet (FAQ)


Q: Are there different strengths or versions of Alcet?

A: Yes, Alcet is offered in both a tablet form and an oral solution form. According to regulatory documents, the medication is available in strengths appropriate for adults and adolescents, and in lower strengths for the pediatric population.


Q: Do I need to stop taking Alcet gradually?

A: Official information notes that a rare risk of moderate to severe itching (pruritus) has been reported after stopping the medicine following long-term daily use. Post-marketing reports indicate that this reaction has been observed to improve when the medication is restarted or when a process of gradual reduction (tapering) is utilized.


Q: Does Alcet cause weight changes?

A: Official data on adverse reactions from clinical trials indicate that weight gain (weight increased) was observed in a small number of patients (less than 1%) during studies involving adults and adolescents. The incidence of this reaction was described in the clinical trial data.


Q: What foods or drinks should be avoided while taking Alcet?

A: Regulatory labeling advises caution regarding certain substances. Official product information states that the concurrent use of alcohol or other central nervous system (CNS) depressants must be avoided. This restriction is based on the potential for additive reductions in alertness and impairment.


Q: Are there any over-the-counter pain relievers that interact with Alcet?

A: Official documents caution that the co-administration of any pain relievers classified as central nervous system (CNS) depressants is restricted. This restriction is due to the potential for an additive effect, which could increase impairment or reduce alertness.


Q: Can Alcet be used during pregnancy?

A: Regulatory sources state that the currently available data on Alcet use in pregnant women are not sufficient to determine a drug-associated risk of adverse developmental outcomes. Official product information does not provide a definitive safety assessment for use during pregnancy.


Q: What happens if I take too much Alcet?

A: If more than the recommended amount of Alcet is taken (an overdose), the official guidance emphasizes the need for urgent medical attention. Regulatory documents instruct users to contact a Poison Control Center immediately if an overdose occurs.


Q: How long does Alcet stay in your system after stopping it?

A: According to the drug's clinical pharmacology profile, the time it takes for half of the medicine to be eliminated from the body, known as the average elimination half-life, is approximately 8 to 9 hours in adults.


Q: Do I need a prescription to get Alcet?

A: The active ingredient in Alcet, levocetirizine dihydrochloride, has regulatory approval for both prescription (Rx) and over-the-counter (OTC) use. Its current status depends on the specific product formulation and official labeling.


Q: Can Alcet interact with herbal supplements?

A: The official patient counseling information covers various substances, including all prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products. Individuals are advised in the labeling to disclose the use of these products to their healthcare provider.


Q: How often do people experience serious side effects from Alcet?

A: Official documents describe serious adverse reactions like urinary retention and generalized hypersensitivity reactions. However, the frequency of many serious reactions is classified as 'Not Known' because they are identified through post-marketing surveillance reports rather than calculated from controlled clinical trials.


Q: Is there a generic version of Alcet available?

A: Yes, the active ingredient in Alcet, levocetirizine dihydrochloride, is approved and manufactured by multiple companies. It is available to consumers under both the brand name and various generic product labels.


Q: Does Alcet have a boxed warning?

A: The regulatory labeling for Alcet (levocetirizine dihydrochloride) does not contain a Boxed Warning (often called a 'black box warning'). This is the most serious type of warning mandated by the FDA for regulated products.


Q: Can Alcet be taken with antacids?

A: Regulatory documents do not list a specific interaction between Alcet and antacids. However, official information advises the disclosure of all current medications to a healthcare provider.


Q: Can Alcet be taken with vitamins?

A: Official patient counseling guidelines advise that the use of all prescription and nonprescription medications, nutritional supplements, and vitamins should be disclosed to a healthcare provider.

How should Alcet be stored and disposed of?

Official Storage and Disposal Requirements

Storage Conditions

Requirement Constraint (Official Labeling)
Temperature Store at controlled room temperature, generally not exceeding 30 C.
Protection Keep the medication in a cool, dry place, protected from excess heat, light, and moisture.
Container Keep the medicine in its original container, tightly closed and away from freezing.
Safety Keep the product out of the sight and reach of children.

Disposal Protocol

The most secure method for disposal of unused or expired Alcet is through an authorized drug take-back program. Since this medicine is not on the FDA's flush list, do not flush it down a toilet or sink.

If a take-back program is unavailable, unused medicine may be disposed of in the household trash. To do this, mix the medication with an undesirable substance, such as used coffee grounds or dirt, seal the mixture in a container, and discard it in the trash. Always scratch out personal information from the prescription label.

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

Available in countries:

Equivalent of Alcet found in:

A-Z Index: