Brand name: ZyrTEC
Drug class: Second Generation Antihistamines

Medically reviewed by Drugs.com on Jan 22, 2025. Written by ASHP.

Introduction

Second generation antihistamine; piperazine-derivative, carboxylic acid metabolite of hydroxyzine.^{1 2 3 11 12 20}

Uses for Cetirizine

Allergic Rhinitis

Self-medication for symptomatic relief of rhinorrhea, sneezing, lacrimation, itching eyes, and/or oronasopharyngeal itching associated with seasonal (e.g., hay fever) allergic rhinitis or other upper respiratory allergies.^{1 2 3 12 20 25 26 27 42 46 49 62 63 68 69 70 71}

Symptomatic relief of perennial (nonseasonal) allergic rhinitis.¹

May be used alone or in fixed combination with pseudoephedrine hydrochloride;^{1 63 69} use fixed-combination preparation only when both antihistamine and nasal decongestant activity are needed concurrently.⁶³

Chronic Idiopathic Urticaria

Self-medication for symptomatic relief of pruritus associated with chronic idiopathic urticaria (e.g., hives);^{1 2 3 12 20 28 29 46 72} not for prevention of chronic idiopathic urticaria or allergic skin reactions.⁷²

Cetirizine Dosage and Administration

Administration

Oral Administration

Administer orally without regard to food.^{1 2 3 12 14 20} May adjust time of administration for individual patient requirements.^{1 3}

Oral solution (syrup): Use only the measuring device (i.e., cup) provided by the manufacturer.^{70 72}

Chewable tablets: Administer with or without water.^{1 71}

Fixed-combination cetirizine/pseudoephedrine tablets (e.g., Zyrtec-D): Swallow whole; do not break or chew.^{63 69}

Dosage

Available as cetirizine hydrochloride; dosage expressed in terms of the salt.¹

Pediatric Patients

Allergic Rhinitis

Seasonal

Self-medication in children 2 to <6 years of age: 2.5 mg once daily (as oral solution); may increase dosage to a maximum of 5 mg daily, given either as a 5-mg dose once daily or, alternatively, as a 2.5-mg dose every 12 hours.^{1 70} (See Pediatric Use under Cautions.)

Self-medication in children ≥6 years of age: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity.^{1 2 3 15 20 22 23 25 68 70 71} In clinical trials, most children ≥12 years of age received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.¹

Self-medication in children ≥12 years of age: 5 mg twice daily (every 12 hours) (in fixed combination with 120 mg pseudoephedrine hydrochloride).^{63 69}

Perennial

Oral

Children 6 months to <2 years of age: 2.5 mg once daily (as oral solution).¹ In children 12–23 months of age, may increase dosage to a maximum of 5 mg daily, given as 2.5 mg every 12 hours.¹ (See Pediatric Use under Cautions.)

Children 2–5 years of age: 2.5 mg once daily (as oral solution);¹ may increase dosage to a maximum of 5 mg daily, given either as a 5-mg dose once daily (as chewable tablets or oral solution) or, alternatively, as a 2.5-mg dose every 12 hours (as oral solution).¹ (See Pediatric Use under Cautions.)

Children ≥6 years of age: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity.^{1 2 3 15 20 22 23 25} In clinical trials, most children ≥12 years of age received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.¹

Children ≥12 years of age: 5 mg twice daily (every 12 hours) (in fixed combination with 120 mg pseudoephedrine hydrochloride).⁶³

Chronic Idiopathic Urticaria

Oral

Children 6 months to <2 years of age: 2.5 mg once daily (as oral solution).¹ In children 12–23 months of age, may increase dosage to a maximum of 5 mg daily, given as 2.5 mg every 12 hours.¹ (See Pediatric Use under Cautions.)

Children 2–5 years of age: 2.5 mg once daily (as oral solution);¹ may increase dosage to a maximum of 5 mg daily, given either as a 5-mg dose once daily (as chewable tablets or oral solution) or, alternatively, as a 2.5-mg dose every 12 hours (as oral solution).¹ (See Pediatric Use under Cautions.)

Self-medication in children ≥6 years of age: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity.^{1 2 3 15 20 22 23 25 72} In clinical trials, most children ≥12 years of age received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.¹

Adults

Allergic Rhinitis

Seasonal

Oral

Self-medication: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity.^{1 2 3 15 20 22 23 25 68 70 71} In clinical trials, most patients received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.¹

Self-medication: 5 mg twice daily (every 12 hours) (in fixed combination with 120 mg pseudoephedrine hydrochloride).^{63 69}

Perennial

Oral

5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity.^{1 2 3 15 20 22 23 25} In clinical trials, most patients received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.¹

5 mg twice daily (every 12 hours) (in fixed combination with 120 mg pseudoephedrine hydrochloride).⁶³

Chronic Idiopathic Urticaria

Oral

Self-medication: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity.^{1 2 3 15 20 22 23 25 72} In clinical trials, most patients received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.¹

Prescribing Limits

Pediatric Patients

Allergic Rhinitis

Oral

Children 12 months to <2 years of age: Maximum 5 mg daily.¹

Self-medication in children 2 to <6 years of age: Maximum 5 mg in 24 hours.⁷⁰ (See Pediatric Use under Cautions.)

Self-medication in children ≥6 years of age: Maximum 10 mg in 24 hours.^{68 70 71}

Self-medication in children ≥12 years of age: Maximum 10 mg daily (in fixed combination with 120 mg pseudoephedrine hydrochloride).⁶⁹ Fixed-combination preparation not recommended for children <12 years of age; contains 120 mg pseudoephedrine hydrochloride, which exceeds recommended single dose in such patients.⁶³

Children ≥12 years of age: In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.¹

Chronic Idiopathic Urticaria

Oral

Children 12 months to 5 years of age: Maximum 5 mg daily.¹

Self-medication in children ≥6 years of age: Maximum 10 mg in 24 hours.⁷²

Children ≥12 years of age: In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.¹

Adults

Allergic Rhinitis

Oral

Self-medication: Maximum 10 mg in 24 hours (alone or in fixed combination with 120 mg pseudoephedrine hydrochloride).^{68 69} In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.¹

Chronic Idiopathic Urticaria

Oral

Self-medication: Maximum 10 mg in 24 hours.⁷² In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.¹

Special Populations

Hepatic Impairment

Children <6 years of age: Use not recommended.¹

Adults and children ≥6 years of age: 5 mg once daily (as chewable or conventional tablets or oral solution).^{1 3}

Adults and children ≥12 years of age: 5 mg once daily (in fixed combination with 120 mg pseudoephedrine hydrochloride).⁶³

Renal Impairment

Children <6 years of age: Use not recommended.¹

Adults and children ≥6 years of age: 5 mg once daily (as chewable or conventional tablets or oral solution) in patients with impaired renal function (e.g., Cl_cr of 11–31 mL/minute) or those on hemodialysis (e.g., Cl_cr <7 mL/minute).^{1 3}

Adults and children ≥12 years of age: 5 mg once daily (in fixed combination with 120 mg pseudoephedrine hydrochloride) in patients with impaired renal function (e.g., Cl_cr of 11–31 mL/minute) or those on hemodialysis (e.g., Cl_cr <7 mL/minute).⁶³

Geriatric Patients

Self-medication in patients ≥65 years of age: 5 mg once daily (as chewable or conventional tablets or oral solution); do not exceed this amount in 24 hours.^{70 71 72}

Cautions for Cetirizine

Contraindications

• Known hypersensitivity to cetirizine, hydroxyzine, or any ingredient in the formulation.^{1 3 63 68 69 70 71 72}

Warnings/Precautions

General Precautions

Prescribing and Dispensing Errors

Ensure accuracy of prescription; similarities in spelling, dosage intervals, and tablet strengths of Zyrtec and Zyprexa (olanzapine, an atypical antipsychotic agent) may result in errors.⁶⁵

CNS Effects

Risk of somnolence;^{1 2 3 5 6 27 28 39 41 42 43 49} caution required when performing hazardous activities requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle).^{1 3} (See Specific Drugs under Interactions.)

Use of Fixed Combinations

When used in fixed combination with pseudoephedrine hydrochloride (e.g., Zyrtec-D), consider the cautions, precautions, and contraindications associated with pseudoephedrine.^{63 69}

Specific Populations

Pregnancy

Chewable or conventional tablets or oral solution: Category B.¹

Fixed-combination cetirizine hydrochloride/pseudoephedrine hydrochloride: Category C.⁶³

Lactation

Distributed into milk.^{1 63} Use not recommended.^{1 3 57 63 68 69 70 71 72}

Pediatric Use

Chewable or conventional tablets or oral solution: Safety and efficacy not established in children <6 months of age; oral solution is the recommended formulation in children <2 years of age.¹

Fixed-combination cetirizine hydrochloride/pseudoephedrine hydrochloride: Safety and efficacy not established in children <12 years of age; use not recommended in this age group.⁶³

Risk of overdosage and toxicity (including death) in children <2 years of age receiving OTC preparations containing antihistamines, cough suppressants, expectorants, and nasal decongestants alone or in combination for relief of symptoms of upper respiratory tract infection.^{66 67} Clinicians should ask caregivers about use of nonprescription cough and cold preparations to avoid overdosage.^a

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults.¹ No overall differences in safety relative to younger patients, but increased sensitivity cannot be ruled out.¹

Select dosage with caution because of age-related decreases in renal function; periodic monitoring of renal function recommended.^{1 3 20 39 46} Dosage adjustment recommended in patients ≥65 years of age.¹ (See Geriatric Patients under Dosage and Administration.)

Hepatic Impairment

Decreased clearance in patients with chronic hepatic impairment.^{1 3 20 39} Dosage adjustment necessary.^{1 3} (See Hepatic Impairment under Dosage and Administration.)

Use not recommended in children <6 years of age with hepatic impairment.¹

Renal Impairment

Decreased clearance in patients with moderate renal impairment (Cl_cr of 11–31 mL/minute) or in those on hemodialysis.^{1 3 20 46 60} Dosage adjustment necessary.¹ (See Renal Impairment under Dosage and Administration.)

Use not recommended in children <6 years of age with renal impairment.¹

Common Adverse Effects

Adults and children ≥12 years of age: Somnolence, fatigue, dry mouth.¹ Insomnia reported with cetirizine hydrochloride-pseudoephedrine hydrochloride fixed combination.⁶³

Children 2–11 years of age: Headache, pharyngitis, abdominal pain.¹

Children 6 months to 2 years of age: Irritability, fussiness, insomnia, fatigue, malaise.¹

Drug Interactions

Metabolized minimally in the liver.² May have low potential for adverse drug interactions associated with metabolic enzyme systems.²

Drugs Affecting Hepatic Microsomal Enzymes

Concomitant administration with drugs known to inhibit CYP microsomal enzymes has not been associated with clinically important changes in ECG parameters (e.g., QT_c intervals).^{1 3 31 56}

Specific Drugs

Cetirizine Pharmacokinetics

Absorption

Bioavailability

Rapidly absorbed from the GI tract following oral administration,^{12 14 47 48} with peak plasma concentrations achieved in about 1 hour.^{1 2 3 4 14 39 46 47 48}

Bioavailability of chewable tablets or oral solution is comparable to that of conventional tablets.¹

Onset

Antihistaminic effect noted in 95% of adults and children at 1 hour.^{1 2 3 6 14 20 43 57}

Duration

Antihistaminic effect persists for about 24 hours.^{1 2 3 6 14 20 43}

Food

Food may decrease peak plasma concentrations and rate of absorption, but does not affect extent of absorption.^{1 2 3 12 20 63}

Distribution

Extent

Distribution into human body tissues not fully elucidated.^{1 3} Appears to be extensively distributed into many body tissues and fluids in animals; ³ brain cetirizine concentrations were <10% of those measured in plasma.²

Distributed into milk.¹

Plasma Protein Binding

Approximately 93%.^{1 3}

Elimination

Metabolism

Undergoes a low degree of first-pass metabolism in the liver; metabolized to limited extent by oxidative O-dealkylation to a metabolite with negligible antihistaminic activity.^{1 2 3 11 14 39 46 47 56 57}

Elimination Route

80% of a dose is excreted in urine, mainly as unchanged drug.^{1 2 4 12 14 20 39 46 47 48 57}

Half-life

Initial distribution half-life is about 3 hours;⁴⁸ terminal elimination half-life is about 8.3 hours.^{1 2 4 12 14 20 39 47 48 57}

Special Populations

In patients with chronic hepatic impairment or moderate renal impairment (e.g., Cl_cr of 11–31 mL/minute) or in those on hemodialysis, half-life is increased and clearance is decreased.^{1 3 20 39}

In geriatric patients (mean: 77 years of age), half-life is increased and clearance is decreased,¹ possibly due to age-related changes in renal function.^{1 3 20 39 46}

In pediatric patients, half-life is decreased and clearance is increased.¹

Stability

Storage

Oral

Tablets and Chewable Tablets

20–25°C (may be exposed to 15–30°C).^{1 63 68 71 72}

Solution

20–25°C (may be exposed to 15–30°C).¹ Also may be refrigerated at 2–8°C.¹

Actions

• Exhibits selective antagonism of peripheral histamine H₁-receptors.^{1 2 3 6 14 20 47 48}

• Antihistaminic effect is comparable to that of astemizole (no longer commercially available in the US), clemastine, chlorpheniramine, diphenhydramine, hydroxyzine, loratadine, pyrilamine, and terfenadine (no longer commercially available in the US).^{2 3 20 43} Tolerance to antihistaminic effect usually does not occur.²

• No appreciable anticholinergic or antiserotonergic effects in animal models,^{56 57} but dry mouth more common with cetirizine than placebo in clinical trials.^{1 3 20 28 41 49}

Advice to Patients

• For self-medication, importance of taking only as directed and not exceeding recommended dosage.⁶⁹

• Risk of somnolence;^{1 2 3 5 6 27 28 39 41 42 43 49} importance of exercising caution when performing activities requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle).^{1 68 69 70 71 72}

• For self-medication with cetirizine in fixed combination with pseudoephedrine, importance of discontinuing therapy and contacting a clinician if symptoms do not improve within 7 days or are accompanied by fever, or if nervousness, dizziness, or sleeplessness occurs.⁶⁹

• For self-medication for management of chronic idiopathic urticaria (e.g., hives), importance of understanding that cetirizine does not prevent hives.⁷² Importance of consulting a clinician before initiating therapy if hives are unusual in color, look bruised or blistered, or do not itch.⁷² Importance of discontinuing therapy and contacting a clinician if symptoms do not improve within 3 days or if hives have persisted for >6 weeks.⁷²

• Importance of understanding that chronic idiopathic urticaria may present with other severe allergic reactions, including anaphylactic shock (e.g., trouble swallowing, swelling of the tongue, trouble speaking, wheezing or trouble breathing, dizziness or loss of consciousness, swelling in or around the mouth, drooling).⁷² These manifestations may occur when hives first appear or up to several hours later and can be life-threatening if not treated immediately.⁷² Importance of immediately seeking emergency help if anaphylactic shock occurs.⁷² If an epinephrine auto-injector has been prescribed, importance of carrying this device at all times; never use cetirizine as a substitute for the epinephrine auto-injector.⁷²

• Importance of discontinuing the drug immediately and informing a clinician if an allergic or hypersensitivity reaction occurs.^{69 70 71}

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as any concomitant illnesses.^{1 63}

• Importance of patients with renal or hepatic impairment, heart disease, hypertension, thyroid disease, diabetes mellitus, glaucoma, or difficulty in urination resulting from prostate enlargement not undertaking self-medication without first consulting a clinician.^{69 70 71 72}

• Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.^{1 63}

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Frequently asked questions

• Should cetirizine be taken at bedtime or upon awakening?
• Can you take antihistamines when pregnant?
• Is Generic Zyrtec Available?

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