Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.
Symptomatic treatment of chronic idiopathic urticaria.
Dosage and Administration
Administration
Oral Administration
Administer orally without regard to food. May adjust time of administration for individual patient requirements.
Take chewable tablets with or without water.
Swallow tablets containing cetirizine hydrochloride in fixed combination with pseudoephedrine hydrochloride (Zyrtec®-D 12 Hour) whole; do not break or chew.
Dosage
Available as cetirizine hydrochloride; dosage expressed in terms of the salt.
Pediatric Patients
Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.
Allergic Rhinitis
Seasonal
Children 2–5 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 (as chewable tablets or oral solution) or, alternatively, as a 2.5-mg dose every 12 hours (as oral solution).
Children ≥6 years of age: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity. 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.
Children ≥12 years of age: 5 mg twice daily (every 12 hours) (as fixed combination with 120 mg pseudoephedrine hydrochloride).
Perennial
Oral
Children 6 months to <2 years of age: 2.5 mg once daily (as oral solution). 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.
Children 2–5 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 (as chewable tablets or oral solution) or, alternatively, as a 2.5-mg dose every 12 hours (as oral solution).
Children ≥6 years of age: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity. 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.
Children ≥12 years of age: 5 mg twice daily (every 12 hours) (as fixed combination with 120 mg pseudoephedrine hydrochloride).
Chronic Idiopathic Urticaria
Oral
Children 6 months to <2 years of age: 2.5 mg once daily (as oral solution). 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.
Children 2–5 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 (as chewable tablets or oral solution) or, alternatively, as a 2.5-mg dose every 12 hours (as oral solution).
Children ≥6 years of age: 5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity. 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.
Adults
Allergic Rhinitis
Oral
5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity. In clinical trials, most patients received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.
5 or 10 mg once daily (as chewable or conventional tablets or oral solution), depending on symptom severity. In clinical trials, most patients received an initial dosage of 10 mg daily; no additional benefit observed with 20-mg daily dosage.
Prescribing Limits
Pediatric Patients
Allergic Rhinitis
Oral
Children 12 months to 5 years of age: Maximum 5 mg daily.
Children ≥12 years of age: In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.
Fixed-combination cetirizine hydrochloride/pseudoephedrine hydrochloride not recommended for children <12 years of age; contains 120 mg pseudoephedrine hydrochloride, which exceeds recommended single dose in such patients.
Chronic Idiopathic Urticaria
Oral
Children 12 months to 5 years of age: Maximum 5 mg daily.
Children ≥12 years of age: In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.
Adults
Allergic Rhinitis
Oral
In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.
Chronic Idiopathic Urticaria
Oral
In clinical trials, a 20-mg daily dosage did not provide additional clinical benefit.
Special Populations
Hepatic Impairment
Children <6 years of age: use not recommended.
Adults and children ≥6 years of age: 5 mg once daily (as chewable or conventional tablets or oral solution).
Adults and children ≥12 years of age: 5 mg once daily (in fixed combination with 120 mg pseudoephedrine hydrochloride).
Renal Impairment
Children <6 years of age: use not recommended.
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., Clcr of 11–31 mL/minute) or those on hemodialysis (e.g., Clcr <7 mL/minute).
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., Clcr of 11–31 mL/minute) or those on hemodialysis (e.g., Clcr <7 mL/minute).
Geriatric Patients
Patients ≥77 years of age: 5 mg once daily (as chewable or conventional tablets or oral solution) recommended.
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.
CNS Effects
Risk of somnolence; caution required when performing hazardous activities requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle). (See Specific Drugs under Interactions.)
Other Precautions
When used in fixed combination with pseudoephedrine hydrochloride (Zyrtec®-D 12 Hour), consider the cautions, precautions, and contraindications associated with pseudoephedrine.
Specific Populations
Pregnancy
Chewable or conventional tablets or oral solution: Category B.
Fixed-combination cetirizine hydrochloride/pseudoephedrine hydrochloride: Category C.
Lactation
Distributed into milk. Use not recommended.
Pediatric Use
Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.
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.
Fixed-combination cetirizine hydrochloride/pseudoephedrine hydrochloride: Safety and efficacy not established in children <12 years of age; use not recommended in this age group.
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. Limited evidence of efficacy for these preparations in this age group; appropriate dosages not established. Use such preparations in children <2 years of age with caution and only as directed by clinician. Clinicians should ask caregivers about use of OTC cough/cold preparations to avoid overdosage.
Geriatric Use
Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults. No overall differences in safety relative to younger patients, but increased sensitivity cannot be ruled out. Select dosage with caution because of age-related decreases in renal function; periodic monitoring of renal function recommended. Dosage adjustment recommended in patients ≥77 years of age. (See Geriatric Patients under Dosage and Administration.)
Hepatic Impairment
Decreased clearance in patients with chronic hepatic impairment. Dosage adjustment necessary. (See Hepatic Impairment under Dosage and Administration.) Use not recommended in children <6 years of age with hepatic impairment.
Renal Impairment
Decreased clearance in patients with moderate renal impairment (Clcr of 11–31 mL/minute) or in those on hemodialysis. Dosage adjustment necessary. (See Renal Impairment under Dosage and Administration.) Use not recommended in children <6 years of age with renal impairment.
Common Adverse Effects
Adults and children ≥12 years of age: somnolence, fatigue, dry mouth. Insomnia reported with cetirizine hydrochloride-pseudoephedrine hydrochloride fixed combination.
Children 6 months to 2 years of age: irritability, fussiness, insomnia, fatigue, malaise.
Interactions
Metabolized minimally in the liver; not known whether metabolized by CYP microsomal enzyme system. May have low potential for adverse drug interactions associated with metabolic enzyme systems.
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., QTc intervals).
Prolongation of QTc interval (with an increase of 17.4 msec) observed with concomitant administration; no clinically important interactions reported
Not considered clinically important
MAO
Potentiated pressor effects of sympathomimetic drugs (e.g., pseudoephedrine)
Avoid concomitant use of fixed-combination preparation containing cetirizine hydrochloride and pseudoephedrine hydrochloride (Zyrtec®-D 12 Hour) with an MAO inhibitor, or for 2 weeks after discontinuance of an MAO inhibitor
Decreased clearance (16%) of cetirizine; disposition of theophylline not altered with concomitant administration
Pharmacokinetics
Absorption
Bioavailability
Rapidly absorbed from the GI tract following oral administration, with peak plasma concentrations achieved in about 1 hour.
Bioavailability of chewable tablets or oral solution is comparable to that of conventional tablets.
Onset
Antihistaminic effect noted in 95% of adults and children at 1 hour.
Duration
Antihistaminic effect persists for about 24 hours.
Food
Food may decrease peak plasma concentrations and rate of absorption, but does not affect extent of absorption.
Distribution
Extent
Distribution into human body tissues not fully elucidated. Appears to be extensively distributed into many body tissues and fluids in animals; brain cetirizine concentrations were <10% of those measured in plasma.
Distributed into milk.
Plasma Protein Binding
Approximately 93%.
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.
Elimination Route
80% of a dose is excreted in urine, mainly as unchanged drug.
Half-life
Initial distribution half-life is about 3 hours; terminal elimination half-life is about 8.3 hours.
Special Populations
In patients with chronic hepatic impairment or moderate renal impairment (e.g., Clcr of 11–31 mL/minute) or in those on hemodialysis, half-life is increased and clearance is decreased.
In geriatric patients (mean: 77 years of age), half-life is increased and clearance is decreased, possibly due to age-related changes in renal function.
In pediatric patients, half-life is decreased and clearance is increased.
Stability
Storage
Oral
Tablets and Chewable Tablets
20–25°C (may be exposed to 15–30°C).
Solution
20–25°C (may be exposed to 15–30°C). Also may be refrigerated at 2–8°C.
Actions
Exhibits selective antagonism of peripheral histamine H1-receptors.
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). Tolerance to antihistaminic effect usually does not occur.
No appreciable anticholinergic or antiserotonergic effects in animal models, but dry mouth more common with cetirizine than placebo in clinical trials.
Advice to Patients
Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.
Risk of somnolence; importance of exercising caution when performing activities requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle).
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.
Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.
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.
This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 09/2009. For the most current and up-to-date pricing information, please visit www.drugstore.com. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.
Remember, keep this and all other medicines out of the reach of children,
never share your medicines with others, and use this medication only for the indication prescribed.
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