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  • cetirizine hydrochloride - Drug Summary

  • CLASSES

    Ocular Anti-Allergics, Antihistamines
    Second Generation Antihistamines

    DEA CLASS

    OTC, Rx

    DESCRIPTION

    Piperazine antihistamine; active metabolite of hydroxyzine; considered "low-sedating"
    Used orally for allergic rhinitis and chronic idiopathic urticaria in adults and pediatric patients; intravenous injection used for acute urticaria
    Ophthalmic solution used for ocular pruritus due to allergic conjunctivitis

    COMMON BRAND NAMES

    All Day Allergy, All Day Allergy Children's, Allergy Relief, Children's Allergy Relief, PediaCare Children's Allergy, Quzyttir, ZERVIATE, Zyrtec, Zyrtec Chewable, Zyrtec Children's, Zyrtec Children's Allergy, ZYRTEC Children's Dye Free, Zyrtec Children's Hives, Zyrtec Dissolve, ZYRTEC Dye Free, Zyrtec Hives Relief, Zyrtec Liquid Gel, Zyrtec Pre-Filled Spoons

    HOW SUPPLIED

    All Day Allergy Children's/Cetirizine/Cetirizine Hydrochloride/Children's Allergy Relief/PediaCare Children's Allergy/Zyrtec/Zyrtec Children's/Zyrtec Children's Allergy/Zyrtec Children's Hives/Zyrtec Pre-Filled Spoons Oral Sol: 1mg, 1mL, 5mg, 5mL
    All Day Allergy Children's/Cetirizine/Cetirizine Hydrochloride/Zyrtec/Zyrtec Chewable/Zyrtec Children's/ZYRTEC Children's Dye Free/ZYRTEC Dye Free Oral Tab Chew: 2.5mg, 5mg, 10mg
    All Day Allergy/Allergy Relief/Cetirizine/Cetirizine Hydrochloride/Zyrtec/Zyrtec Hives Relief Oral Tab: 5mg, 10mg
    Cetirizine Ophthalmic Sol: 1mL, 2.4mg
    Cetirizine/Cetirizine Hydrochloride/Zyrtec Liquid Gel Oral Cap: 10mg
    Quzyttir Intravenous Inj: 1mL, 10mg
    Zyrtec Children's Allergy Oral Tab Orally Dis: 10mg

    DOSAGE & INDICATIONS

    For the management of symptoms of seasonal allergies or perennial allergies, including allergic rhinitis.
    Oral dosage (tablets, orally disintegrating tablets, and liquid gels)
    Adults

    5 to 10 mg PO once daily, depending on severity of symptoms.

    Geriatric Adults

    5 to 10 mg orally once daily; a lower dose of 5 mg orally once daily is the recommended dosage for geriatric patients aged 77 years and older. Use the lowest effective dosage. Elderly patients are more sensitive to anticholinergic effects. OTC labeling recommends patients aged 65 years and older ask a doctor before use.

    Children and Adolescents 6 years and older

    5 to 10 mg orally once daily, depending on severity of symptoms. Alternatively, 5 mg orally twice daily may better maintain symptom control for some patients. A multicenter double-blind clinical trial was conducted in 124 pediatric patients (ages 6 to 12 years) who received 5 mg twice daily of cetirizine or placebo for allergic rhinoconjunctivitis. Patients receiving cetirizine had more symptom-free or mild symptom days compared to the placebo group (56.2% vs. 29.7%). In clinical trials, most patients older than 12 years began at the 10 mg dose.

    Oral dosage (chewable tablets)
    Adults

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Geriatric Adults

    5 to 10 mg orally once daily; a lower dose of 5 mg orally once daily is the recommended dosage for geriatric patients aged 77 years and older. Use the lowest effective dosage. Elderly patients are more sensitive to anticholinergic effects. OTC labeling recommends patients aged 65 years and older ask a doctor before use.

    Children and Adolescents 6 years and older

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Children 2 to 5 years

    Chewable tablets are generally not recommended as initial therapy. Initial dose is 2.5 mg orally once daily given as liquid formulation. If needed, the dose may be increased to 5 mg once daily using the chewable tablet.

    Oral dosage (syrup and solution)
    Adults

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Geriatric Adults

    5 to 10 mg orally once daily; a lower dose of 5 mg orally once daily is the recommended dosage for patients aged 77 years and older. Use the lowest effective dosage. Geriatric patients are more sensitive to anticholinergic effects. OTC labeling recommends patients aged 65 years and older ask a doctor before use.

    Children and Adolescents 6 years and older

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Children 2 to 5 years

    2.5 mg orally once daily. If needed, may increase to 5 mg orally once daily or 2.5 mg orally twice daily.

    Children less than 2 years of age

    2.5 mg orally once daily; prescription use only for perennial allergic rhinitis. If needed, may increase to 2.5 mg orally every 12 hours.

    Infants 6 months and older

    2.5 mg orally once daily; prescription use only for perennial allergic rhinitis.

    For the treatment of symptoms of chronic idiopathic urticaria (e.g., relief of pruritus, reduction in the size and number of hives).
    Oral dosage (tablets)
    Adults

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Geriatric Adults

    5 to 10 mg orally once daily; a lower dose of 5 mg orally once daily is the recommended dosage for geriatric patients aged 77 years and older. Use the lowest effective dosage. Elderly patients are more sensitive to anticholinergic effects. OTC labeling recommends patients aged 65 years and older ask a doctor before use.

    Children and Adolescents 6 years and older

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Oral dosage (chewable tablets)
    Adults

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Geriatric Adults

    5 to 10 mg orally once daily; a lower dose of 5 mg orally once daily is the recommended dosage for geriatric patients aged 77 years and older. Use the lowest effective dosage. Geriatric patients are more sensitive to anticholinergic effects. OTC labeling recommends patients aged 65 years and older ask a doctor before use.

    Children and Adolescents 6 years and older

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Children 2 to 5 years

    Chewable tablets generally are not recommended as initial therapy. Initial dose is 2.5 mg orally once daily given as liquid formulation. If needed, the dose may be increased to 5 mg once daily using the chewable tablet.

    Oral dosage (syrup and solution)
    Adults

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Geriatric Adults

    5 to 10 mg orally once daily; a lower dose of 5 mg orally once daily is the recommended dosage for geriatric patients aged 77 years and older. Use the lowest effective dosage. Elderly patients are more sensitive to anticholinergic effects. OTC labeling recommends patients aged 65 years and older ask a doctor before use.

    Children and Adolescents 6 years and older

    5 to 10 mg orally once daily, depending on severity of symptoms.

    Children 2 to 5 years

    2.5 mg orally once daily. If needed, may increase to 5 mg orally once daily or 2.5 mg orally twice daily.

    Children less than 2 years of age

    2.5 mg orally once daily. If needed, may increase to 2.5 mg every 12 hours.

    Infants 6 months and older

    2.5 mg orally once daily.

    For the treatment of ocular pruritus associated with allergic conjunctivitis.
    Ophthalmic dosage
    Adults

    1 drop in the affected eye(s) twice daily (approximately 8 hours apart).

    Children and Adolescents 2 to 17 years

    1 drop in the affected eye(s) twice daily (approximately 8 hours apart).

    For the treatment of acute urticaria.
    Intravenous dosage
    Adults

    10 mg IV once every 24 hours as needed.

    Children and Adolescents 12 years and older

    10 mg IV once every 24 hours as needed.

    Children 6 to 11 years

    5 mg or 10 mg IV (depending on symptom severity) once every 24 hours as needed.

    Children 1 to 5 years

    2.5 mg IV once every 24 hours as needed.

    Infants 6 months and older

    2.5 mg IV once every 24 hours as needed.

    For the symptomatic treatment of atopic dermatitis†.
    Oral dosage
    Children 6 to 12 years

    5 to 10 mg PO once daily may be beneficial. In a small study (n = 23), cetirizine 5 mg/day for patients weighing 30 kg or less and 10 mg/day for those more than 30 kg was associated with a more rapid resolution of pruritus, a significant clearing of all atopic dermatitis manifestations, and a significant reduction in the use of concurrent topical medications when compared to placebo.

    Children 3 to 5 years

    Specific dosing recommendations are not available for children 3 to 5 years old; based on dosing used for allergic rhinitis, consider 2.5 mg PO once daily. May increase to 5 mg once daily or 2.5 mg every 12 hours if needed.

    Children 1 to 2 years

    0.25 mg/kg/dose PO twice daily may be beneficial for some patients. In a multicenter trial (n = 795), cetirizine was associated with fewer episodes of urticaria in all patients and a reduction in topical steroid use in patients with severe symptoms compared to placebo; overall reduction in disease severity scores did not differ between groups.

    †Indicates off-label use

    MAXIMUM DOSAGE

    Adults

    10 mg/day PO; 10 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.

    Geriatric

    Less than 77 years: 10 mg/day PO; 10 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.
    77 years and older: 5 mg/day PO; 10 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.

    Adolescents

    10 mg/day PO; 10 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.

    Children

    6 years and older: 10 mg/day PO; 10 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.
    3 to 5 years: 5 mg/day PO; 2.5 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.
    2 years: 5 mg/day PO (FDA-approved); 0.25 mg/kg/dose PO twice daily has been used off-label for atopic dermatitis; 2.5 mg/day IV. 2 drops/day per affected eye for ophthalmic solution.
    1 year: 5 mg/day PO (FDA-approved); 0.25 mg/kg/dose PO twice daily has been used off-label for atopic dermatitis; 2.5 mg/day IV. Safety and efficacy not established for ophthalmic solution.

    Infants

    6 months and older: 2.5 mg/day PO; 2.5 mg/day IV. Safety and efficacy not established for ophthalmic solution.
    Younger than 6 months: Safety and efficacy have not been established.

    Neonates

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Oral Dosage forms
    Adults, adolescents, and children 6 years and older: No more than 5 mg PO once daily.
    Children less than 6 years: Use is not recommended due to lack of data in hepatically-impaired pediatric patients in this age group.
     
    Intravenous Injection
    No dosage adjustment is required in patients with hepatic impairment; however these patients should be monitored for antihistaminic side effects.

    Renal Impairment

    Oral Dosage Forms
    FDA-approved recommendations for patients with renal impairment :
    Adults, Adolescents, and Children 6 years and older:
    CrCl more than 31 mL/minute: No dosage adjustment needed.
    CrCl 31 mL/minute or less: No more than 5 mg PO once daily.
    Children less than 6 years: Use not recommended due to a lack of data.
     
    Alternative recommendations for pediatric patients with renal impairment :
    CrCl 30 mL/minute/1.73 m2 or more: No dosage adjustment needed.
    CrCl 10 to 29 mL/minute/1.73 m2: Administer 50% of the usual dosage.
    CrCl less than 10 mL/minute/1.73 m2: Not recommended.
     
    Intravenous Injection
    No dosage adjustment is required in patients with moderate and severe renal impairment; however these patients should be monitored for antihistaminic side effects.
     
    Intermittent hemodialysis
    Oral Dosage Forms: Follow dosage recommendations as for CrCl 31 mL/minute or less; cetirizine is not removed by hemodialysis.
    Intravenous Injection: No dosage adjustment is required.

    ADMINISTRATION

    Oral Administration

    The time of cetirizine administration (morning or evening) can be adjusted to meet individual patient needs.
    May be administered without regard to meals.

    Oral Solid Formulations

    Capsules: Swallow whole, do not cut, chew, or crush.
    Orally disintegrating tablets: Tablet melts in mouth. May be taken with or without water.
    Chewable tablets: Chew tablet before swallowing. May be taken with or without water.

    Oral Liquid Formulations

    Administer using a calibrated measuring device.

    Injectable Administration

    Cetirizine injection is for intravenous administration only.
    Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.

    Intravenous Administration

    IV Push
    Dilution is not necessary.
    Administer cetirizine injection as an intravenous push over a period of 1 to 2 minutes.
    The vial is for single-use only; discard any unused portion.

    Ophthalmic Administration

    Instruct patients on proper instillation of the ophthalmic solution.
    Wash hands before and after use.
    Remove contact lenses prior to instillation of the dose. Contact lenses may be reinserted 10 minutes after the dose has been administered.
    Do not remove the cap from the multi-dose bottle or remove the single-use container from the original foil pouch until immediately prior to use.
    Take care to avoid contamination. Do not touch the dropper tip of the multi-dose bottle or the tip of the single-use container to the eye, fingertips, or other surfaces.
    Tilt the head back slightly and pull the lower eyelid down with the index finger to form a pouch. Squeeze 1 drop into the pouch of each affected eye and gently close eyes. Do not blink. If administering the dose via a single-use container, 1 container can be used to dose both eyes.
    Single-use containers should remain in original foil patch until ready to use.
    Keep the multi-dose bottle closed when not in use. Discard the single-use container after use.

    STORAGE

    All Day Allergy :
    - Store between 68 to 77 degrees F
    All Day Allergy Children's:
    - Protect from light
    - Store between 68 to 77 degrees F
    Allergy Relief:
    - Store between 68 to 77 degrees F
    Children's Allergy Relief:
    - Protect from light
    - Store between 68 to 77 degrees F
    PediaCare Children's Allergy:
    - Store between 68 to 77 degrees F
    Quzyttir:
    - Discard unused portion. Do not store for later use.
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
    ZERVIATE:
    - Protect from light
    - Store between 59 to 77 degrees F
    - Store unused product in foil pouch
    Zyrtec:
    - Protect from light
    - Store between 68 to 77 degrees F
    Zyrtec Chewable:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Zyrtec Children's:
    - Protect from light
    - Store between 68 to 77 degrees F
    Zyrtec Children's Allergy :
    - Avoid excessive humidity
    - Store between 68 to 77 degrees F
    ZYRTEC Children's Dye Free:
    - Store between 68 to 77 degrees F
    Zyrtec Children's Hives :
    - Protect from light
    - Store between 68 to 77 degrees F
    Zyrtec Dissolve:
    - Avoid excessive humidity
    - Store between 68 to 77 degrees F
    ZYRTEC Dye Free:
    - Store between 68 to 77 degrees F
    Zyrtec Hives Relief :
    - Store between 68 to 77 degrees F
    Zyrtec Liquid Gel :
    - Avoid excessive heat (above 104 degrees F)
    - Avoid excessive humidity
    - Protect from light
    - Store between 68 to 77 degrees F
    Zyrtec Pre-Filled Spoons:
    - Protect from light
    - Store between 68 to 77 degrees F
    Zyrtec Syrup:
    - Store between 68 to 77 degrees F

    CONTRAINDICATIONS / PRECAUTIONS

    General Information

    Cetirizine has less affinity than some H1-blockers for calcium channel, alpha-adrenergic, D2-dopamine, 5HT2-serotonin and muscarinic receptors. A reduction in anticholinergic effects may mean that some of the restrictions to the use of older H1-blockers may not apply to cetirizine.

    Hydroxyzine hypersensitivity

    Cetirizine is contraindicated for use in patients with a known hypersensitivity to the drug or to any of the formulation components or who have known hydroxyzine hypersensitivity or levocetirizine hypersensitivity. Cetirizine is a known human metabolite of hydroxyzine, and levocetirizine is an enantiomer of cetirizine.  

    Coadministration with other CNS depressants, driving or operating machinery, ethanol ingestion

    In clinical trials, drowsiness has been reported in some patients taking cetirizine; therefore patients receiving cetirizine should be advised to avoid driving or operating machinery until the effects of the drug are known. Because the effects of ethanol or other CNS depressants may be additive with antihistamines, ethanol ingestion should be avoided and coadministration with other CNS depressants should be approached with caution.

    Renal failure, renal impairment

    In patients with moderate to severe renal impairment (CrCl 31 mL/minute or less) or renal failure, dosage reduction of oral cetirizine is recommended; cetirizine is not appreciably removed during dialysis. No dosage adjustment of cetirizine injection for acute urticaria is required in patients with moderate and severe renal impairment and in patients on dialysis; however these patients should be monitored for antihistaminic side effects.

    Hepatic disease

    Dosage adjustments of oral cetirizine are suggested for patients with hepatic disease as exposure is increased in hepatically impaired patients and the drug clearance rate is reduced. No dosage adjustment of intravenous cetirizine is required in patients with hepatic impairment; however these patients should be monitored for antihistaminic side effects.

    Pregnancy

    There are no adequate or well-controlled studies with the use of cetirizine during human pregnancy. Animal studies do not reveal a risk for teratogenesis, even at doses greatly exceeding the maximum recommended daily human dose on mg/m2 basis; however, animal studies are not always predictive of human response. Use cetirizine during pregnancy only if the potential benefit justifies the potential risk to the fetus.[40967] [61987] Self-medication with cetirizine (nonprescription or OTC formulations) during pregnancy is not recommended. Pregnant patients should see their health care professional for a proper diagnosis and treatment recommendations. The American College of Obstetricians and Gynecologists and the American College of Allergy, Asthma, and Immunology consider cetirizine and loratadine as acceptable alternatives in pregnancy, preferably after the first trimester, when first-generation antihistamines are not tolerated.[46717]

    Breast-feeding

    Cetirizine is excreted in human breast milk after oral administration. It is not known whether systemic absorption from the topical ocular administration of cetirizine could produce detectable quantities in breast milk. There is no adequate information regarding the effects of cetirizine on the breast-fed infant or the effects on milk production. Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for cetirizine and any potential adverse effects on the breast-fed child from cetirizine. The British Society for Allergy and Clinical Immunology recommends cetirizine at the lowest dose as a preferred antihistamine in breast-feeding women. Loratadine is also usually considered compatible with breast-feeding.

    Geriatric

    A decline in renal function in the geriatric adult (mean age 77 years) was responsible for prolonged half-life of oral cetirizine and reduced total clearance; oral cetirizine dosage adjustment is recommended for elderly patients 77 years and older. No safety differences have been noted in clinical use for elderly (65 years and older) vs. younger adults. No dosage adjustment of cetirizine intravenous injection is required in geriatric adults; however, these patients should be monitored for antihistaminic side effects. The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents (e.g., geriatric adults) of long-term care facilities. According to the OBRA guidelines, cough, cold, and allergy medications should be used only for a limited duration (less than 14 days) unless there is documented evidence of enduring symptoms that cannot otherwise be alleviated and for which a cause cannot be identified and corrected.

    Contact lenses

    Instruct patients to remove contact lenses prior to ophthalmic administration of cetirizine. The preservative, benzalkonium chloride, may be absorbed by soft contact lenses. Contact lenses may be reinserted 10 minutes after dose administration; however, advise patients not to wear contact lenses if their eyes are red.

    ADVERSE REACTIONS

    Severe

    bronchospasm / Rapid / 1.9-3.1
    myelitis / Delayed / 0-2.0
    angioedema / Rapid / 0-2.0
    heart failure / Delayed / 0-2.0
    visual impairment / Early / 0-2.0
    ocular hemorrhage / Delayed / 0-2.0
    ocular hypertension / Delayed / 0-2.0
    hearing loss / Delayed / 0-2.0
    seizures / Delayed / Incidence not known
    anaphylactoid reactions / Rapid / Incidence not known
    glomerulonephritis / Delayed / Incidence not known
    suicidal ideation / Delayed / Incidence not known
    hemolytic anemia / Delayed / Incidence not known
    fetal death / Delayed / Incidence not known

    Moderate

    conjunctival hyperemia / Early / 1.0-7.0
    dysphonia / Delayed / 0-2.0
    hyperesthesia / Delayed / 0-2.0
    ataxia / Delayed / 0-2.0
    migraine / Early / 0-2.0
    hypertonia / Delayed / 0-2.0
    gastritis / Delayed / 0-2.0
    constipation / Delayed / 0-2.0
    melena / Delayed / 0-2.0
    hemorrhoids / Delayed / 0-2.0
    stomatitis / Delayed / 0-2.0
    atopic dermatitis / Delayed / 0-2.0
    furunculosis / Delayed / 0-2.0
    dyspnea / Early / 0-2.0
    sinus tachycardia / Rapid / 0-2.0
    palpitations / Early / 0-2.0
    hypertension / Early / 0-2.0
    chest pain (unspecified) / Early / 0-2.0
    cystitis / Delayed / 0-2.0
    urinary incontinence / Early / 0-2.0
    dysuria / Early / 0-2.0
    urinary retention / Early / 0-2.0
    hematuria / Delayed / 0-2.0
    blurred vision / Early / 0-2.0
    conjunctivitis / Delayed / 0-2.0
    dehydration / Delayed / 0-2.0
    diabetes mellitus / Delayed / 0-2.0
    myasthenia / Delayed / 0-2.0
    euphoria / Early / 0-2.0
    depression / Delayed / 0-2.0
    amnesia / Delayed / 0-2.0
    vaginitis / Delayed / 0-2.0
    lymphadenopathy / Delayed / 0-2.0
    peripheral edema / Delayed / 0-2.0
    edema / Delayed / 0-2.0
    elevated hepatic enzymes / Delayed / 0-1.0
    hot flashes / Early / 0-1.0
    dyskinesia / Delayed / Incidence not known
    myoclonia / Delayed / Incidence not known
    hyperbilirubinemia / Delayed / Incidence not known
    hepatitis / Delayed / Incidence not known
    cholestasis / Delayed / Incidence not known
    hypotension / Rapid / Incidence not known
    hallucinations / Early / Incidence not known
    thrombocytopenia / Delayed / Incidence not known

    Mild

    headache / Early / 0-14.0
    drowsiness / Early / 1.9-14.0
    pharyngitis / Delayed / 2.8-6.2
    abdominal pain / Early / 4.0-6.0
    fatigue / Early / 5.9-5.9
    xerostomia / Early / 5.0-5.0
    cough / Delayed / 2.8-4.4
    epistaxis / Delayed / 1.9-3.7
    diarrhea / Early / 1.9-3.1
    nausea / Early / 2.0-3.0
    vomiting / Early / 2.0-3.0
    paresthesias / Delayed / 0-2.0
    ptosis / Delayed / 0-2.0
    hypoesthesia / Delayed / 0-2.0
    vertigo / Early / 0-2.0
    dizziness / Early / 2.0-2.0
    hyperkinesis / Delayed / 0-2.0
    syncope / Early / 0-2.0
    tremor / Early / 0-2.0
    insomnia / Early / 0-2.0
    weight gain / Delayed / 0-2.0
    appetite stimulation / Delayed / 0-2.0
    dental caries / Delayed / 0-2.0
    flatulence / Early / 0-2.0
    dyspepsia / Early / 0-2.0
    tongue discoloration / Delayed / 0-2.0
    anorexia / Delayed / 0-2.0
    eructation / Early / 0-2.0
    acne vulgaris / Delayed / 0-2.0
    hypertrichosis / Delayed / 0-2.0
    xerosis / Delayed / 0-2.0
    photosensitivity / Delayed / 0-2.0
    urticaria / Rapid / 0-2.0
    maculopapular rash / Early / 0-2.0
    hyperkeratosis / Delayed / 0-2.0
    purpura / Delayed / 0-2.0
    hyperhidrosis / Delayed / 0-2.0
    seborrhea / Delayed / 0-2.0
    rash / Early / 0-2.0
    pruritus / Rapid / 0-2.0
    hyperventilation / Early / 0-2.0
    rhinitis / Early / 0-2.0
    sinusitis / Delayed / 0-2.0
    polyuria / Early / 0-2.0
    increased urinary frequency / Early / 0-2.0
    xerophthalmia / Early / 0-2.0
    ocular pain / Early / 0-2.0
    otalgia / Early / 0-2.0
    tinnitus / Delayed / 0-2.0
    polydipsia / Early / 0-2.0
    arthropathy / Delayed / 0-2.0
    arthralgia / Delayed / 0-2.0
    muscle cramps / Delayed / 0-2.0
    myalgia / Early / 0-2.0
    agitation / Early / 0-2.0
    libido decrease / Delayed / 0-2.0
    anxiety / Delayed / 0-2.0
    emotional lability / Early / 0-2.0
    nightmares / Early / 0-2.0
    menstrual irregularity / Delayed / 0-2.0
    menorrhagia / Delayed / 0-2.0
    leukorrhea / Delayed / 0-2.0
    mastalgia / Delayed / 0-2.0
    dysmenorrhea / Delayed / 0-2.0
    fever / Early / 0-2.0
    malaise / Early / 0-2.0
    parosmia / Delayed / 0-2.0
    dysgeusia / Early / 0-2.0
    flushing / Rapid / 0-2.0
    asthenia / Delayed / 0-2.0
    pallor / Early / 0-2.0
    back pain / Delayed / 0-2.0
    hypersalivation / Early / Incidence not known

    DRUG INTERACTIONS

    Acetaminophen; Caffeine; Dihydrocodeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Acetaminophen; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Acetaminophen; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Acetaminophen; Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Acetaminophen; Pentazocine: (Moderate) Concurrent use of cetirizine/levocetirizine with pentazocine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Alfentanil: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Alprazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Amobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Amoxapine: (Moderate) Concurrent use of cetirizine/levocetirizine with heterocyclic antidepressants should generally be avoided. Coadministration may increase the risk of anticholinergic and CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive anticholinergic effects, sedation, and somnolence.
    Apomorphine: (Moderate) Concurrent use of cetirizine/levocetirizine with apomorphine should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
    Aripiprazole: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Asenapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Aspirin, ASA; Butalbital; Caffeine: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Aspirin, ASA; Butalbital; Caffeine; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Aspirin, ASA; Caffeine; Orphenadrine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Aspirin, ASA; Carisoprodol: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Aspirin, ASA; Carisoprodol; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Aspirin, ASA; Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Atropine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    Atropine; Difenoxin: (Moderate) Concurrent administration of diphenoxylate/difenoxin with cetirizine can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    Atropine; Edrophonium: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    atypical antipsychotic: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Baclofen: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Barbiturates: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Belladonna; Opium: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and belladonna use. Concomitant use may result in additive anticholinergic adverse effects.
    Benzhydrocodone; Acetaminophen: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Benzodiazepines: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
    Benztropine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and benztropine use. Concomitant use may result in additive anticholinergic adverse effects.
    Brexpiprazole: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Budesonide; Glycopyrrolate; Formoterol: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
    Buprenorphine: (Major) Reserve concomitant use of buprenorphine and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Buprenorphine; Naloxone: (Major) Reserve concomitant use of buprenorphine and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Butabarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Butalbital; Acetaminophen: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Butalbital; Acetaminophen; Caffeine: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Butalbital; Acetaminophen; Caffeine; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Butorphanol: (Moderate) Concurrent use of cetirizine/levocetirizine with butorphanol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Calcium, Magnesium, Potassium, Sodium Oxybates: (Moderate) Concurrent use of cetirizine/levocetirizine with sodium oxybate should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Cannabidiol: (Moderate) Concurrent use of cetirizine/levocetirizine with cannabidiol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Capsaicin; Metaxalone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Carbidopa; Levodopa; Entacapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
    Cariprazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Carisoprodol: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Celecoxib; Tramadol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Cenobamate: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cenobamate and cetirizine. Concurrent use may result in additive CNS depression.
    Chlordiazepoxide: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Chlordiazepoxide; Amitriptyline: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Chlordiazepoxide; Clidinium: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Chlorpheniramine; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Chlorpheniramine; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Chlorthalidone; Clonidine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and clonidine due to the risk for additive CNS depression.
    Chlorzoxazone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Clonazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Clonidine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and clonidine due to the risk for additive CNS depression.
    Clorazepate: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Clozapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Codeine; Guaifenesin: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Codeine; Guaifenesin; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Codeine; Phenylephrine; Promethazine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Codeine; Promethazine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    COMT inhibitors: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
    Cyclobenzaprine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Dantrolene: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
    Desloratadine: (Minor) Although desloratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of desloratadine with CNS depressants such as other H1-blockers.
    Desloratadine; Pseudoephedrine: (Minor) Although desloratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of desloratadine with CNS depressants such as other H1-blockers.
    Deutetrabenazine: (Moderate) Concurrent use of cetirizine/levocetirizine with deutetrabenazine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Dexmedetomidine: (Moderate) Concurrent use of cetirizine/levocetirizine with dexmedetomidine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of dexmedetomidine; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Diazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Dicyclomine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and dicyclomine use. Concomitant use may result in additive anticholinergic adverse effects.
    Difelikefalin: (Moderate) Monitor for dizziness, somnolence, mental status changes, and gait disturbances if concomitant use of difelikefalin with CNS depressants is necessary. Concomitant use may increase the risk for these adverse reactions.
    Diphenoxylate; Atropine: (Moderate) Concurrent administration of diphenoxylate/difenoxin with cetirizine can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    Dronabinol: (Moderate) Additive drowsiness may occur if cetirizine/levocetirizine is administered with other drugs that depress the CNS, including dronabinol.
    Droperidol: (Moderate) Concurrent use of cetirizine/levocetirizine with droperidol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Entacapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
    Esketamine: (Moderate) Closely monitor patients receiving esketamine and cetirizine for sedation and other CNS depressant effects. Instruct patients who receive a dose of esketamine not to drive or engage in other activities requiring alertness until the next day after a restful sleep.
    Estazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Eszopiclone: (Moderate) Concurrent use of cetirizine/levocetirizine with eszopiclone should generally be avoided. Concurrent use of eszopiclone with other CNS depressants increases the risk for CNS depression and complex sleep-related behaviors (e.g., driving, talking, eating, or performing other activities while not fully awake). If concurrent use is necessary, patients should be instructed to contact their provider immediately if these symptoms or behaviors occur.
    Ethanol: (Major) Advise patients to avoid alcohol consumption while taking CNS depressants. Alcohol consumption may result in additive CNS depression.
    Etomidate: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Fenfluramine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of fenfluramine and cetirizine. Concurrent use may result in additive CNS depression.
    Fentanyl: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Flavoxate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
    Flibanserin: (Moderate) Concurrent use of cetirizine/levocetirizine with flibanserin should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Flurazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Food: (Major) Advise patients to avoid cannabis use while taking CNS depressants due to the risk for additive CNS depression and potential for other cognitive adverse reactions.
    Gabapentin: (Moderate) Monitor for respiratory depression and sedation during concomitant cetirizine and gabapentin use; consider starting gabapentin at a low dose. Concomitant use increases the risk for additive CNS depression.
    General anesthetics: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
    Glycopyrrolate; Formoterol: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
    Guaifenesin; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Guaifenesin; Hydrocodone; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Guanfacine: (Moderate) Concurrent use of cetirizine/levocetirizine with guanfacine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Haloperidol: (Moderate) Concurrent use of cetirizine/levocetirizine with haloperidol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Heparin: (Minor) Antihistamines may partially counteract the anticoagulant actions of heparin, according to the product labels. However, this interaction is not likely of clinical significance since heparin therapy is adjusted to the partial thromboplastin time (aPTT) and other clinical parameters of the patient.
    Heterocyclic antidepressants: (Moderate) Concurrent use of cetirizine/levocetirizine with heterocyclic antidepressants should generally be avoided. Coadministration may increase the risk of anticholinergic and CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive anticholinergic effects, sedation, and somnolence.
    Homatropine; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and homatropine use. Concomitant use may result in additive anticholinergic adverse effects.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Concurrent use of cetirizine/levocetirizine with methyldopa should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Hydrocodone; Ibuprofen: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Hydrocodone; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Hydromorphone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Hyoscyamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
    Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
    Ibuprofen; Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Iloperidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Indacaterol; Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
    Isocarboxazid: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
    Isoflurane: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Ketamine: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Lemborexant: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lemborexant and cetirizine. Dosage adjustments of lemborexant and cetirizine may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants.
    Levorphanol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Lofexidine: (Moderate) Concurrent use of cetirizine/levocetirizine with lofexidine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Lopinavir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
    Loratadine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
    Loratadine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
    Lorazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Loxapine: (Moderate) Concurrent use of cetirizine/levocetirizine with loxapine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Lumateperone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Lurasidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Maprotiline: (Moderate) Concurrent use of cetirizine/levocetirizine with heterocyclic antidepressants should generally be avoided. Coadministration may increase the risk of anticholinergic and CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive anticholinergic effects, sedation, and somnolence.
    Melatonin: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and melatonin due to the risk for additive CNS depression.
    Meperidine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Meperidine; Promethazine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Meprobamate: (Moderate) Concurrent use of cetirizine/levocetirizine with meprobamate should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Metaxalone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Methadone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
    Methohexital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Methscopolamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and methscopolamine use. Concomitant use may result in additive anticholinergic adverse effects.
    Methyldopa: (Moderate) Concurrent use of cetirizine/levocetirizine with methyldopa should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Midazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Mirtazapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and mirtazapine due to the risk for additive CNS depression.
    Molindone: (Moderate) Concurrent use of cetirizine/levocetirizine with molindone should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Monoamine oxidase inhibitors: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
    Morphine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Morphine; Naltrexone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Nabilone: (Moderate) Additive drowsiness may occur if cetirizine or levocetirizine is administered with other drugs that depress the CNS, such as nabilone.
    Nalbuphine: (Moderate) Concurrent use of cetirizine/levocetirizine with nalbuphine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Nefazodone: (Moderate) Concurrent use of cetirizine/levocetirizine with nefazodone should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Nirmatrelvir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
    Olanzapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Olanzapine; Fluoxetine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Olanzapine; Samidorphan: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Oliceridine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
    Opiate Agonists: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Opicapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
    Orphenadrine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Oxazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Oxybutynin: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and oxybutynin use. Concomitant use may result in additive anticholinergic adverse effects.
    Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Oxymorphone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Paliperidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Pentazocine: (Moderate) Concurrent use of cetirizine/levocetirizine with pentazocine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Pentazocine; Naloxone: (Moderate) Concurrent use of cetirizine/levocetirizine with pentazocine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Pentobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Perampanel: (Moderate) Concurrent use of cetirizine/levocetirizine with perampanel should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Phenelzine: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
    Phenobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and scopolamine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    Pimavanserin: (Moderate) Concurrent use of cetirizine/levocetirizine with pimavanserin should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Pimozide: (Moderate) Concurrent use of cetirizine/levocetirizine with pimozide should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Pramipexole: (Moderate) Concurrent use of cetirizine/levocetirizine with pramipexole should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
    Pregabalin: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and pregabalin due to the risk for additive CNS depression.
    Primidone: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Propantheline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and propantheline use. Concomitant use may result in additive anticholinergic adverse effects.
    Propofol: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Quazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Quetiapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Ramelteon: (Moderate) Concurrent use of cetirizine/levocetirizine with ramelton should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Rasagiline: (Moderate) Concurrent use of cetirizine/levocetirizine with rasagiline should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
    Remifentanil: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Remimazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Risperidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
    Ropinirole: (Moderate) Concurrent use of cetirizine/levocetirizine with ropinirole should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
    Rotigotine: (Moderate) Concurrent use of cetirizine/levocetirizine with rotigotine should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
    Safinamide: (Moderate) Concurrent use of cetirizine/levocetirizine with safinamide should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
    Scopolamine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and scopolamine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
    Secobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Sedating H1-blockers: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and sedating H1-blockers. Concomitant use may result in additive CNS depression or anticholinergic effects.
    Selegiline: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and selegiline due to the risk for additive CNS depression.
    Sevoflurane: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
    Sincalide: (Moderate) Sincalide-induced gallbladder ejection fraction may be affected by concurrent medications, including H1-blockers. False study results are possible; thorough patient history is important in the interpretation of procedure results.
    Skeletal Muscle Relaxants: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
    Sodium Oxybate: (Moderate) Concurrent use of cetirizine/levocetirizine with sodium oxybate should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Stiripentol: (Moderate) Concurrent use of cetirizine/levocetirizine with stiripentol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Sufentanil: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Suvorexant: (Moderate) Concurrent use of cetirizine/levocetirizine with suvorexant should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Tapentadol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Tasimelteon: (Moderate) Concurrent use of cetirizine/levocetirizine with tasimelteon should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Temazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Tetrabenazine: (Moderate) Concurrent use of cetirizine/levocetirizine with tetrabenazine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Thalidomide: (Moderate) Concurrent use of cetirizine/levocetirizine with thalidomide should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Theophylline, Aminophylline: (Minor) Large doses of aminophylline may reduce the clearance of cetirizine/levocetirizine. Monitor the patient clinically for an altered response to cetirizine/levocetirizine if coadministered with aminophylline. (Minor) Large doses of theophylline may reduce the clearance of cetirizine/levocetirizine. Monitor the patient clinically for increased cetirizine/levocetirizine-related adverse effects if coadministered with theophylline.
    Thiothixene: (Moderate) Concurrent use of cetirizine/levocetirizine with thiothixene should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Tolcapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
    Tramadol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Tramadol; Acetaminophen: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
    Tranylcypromine: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
    Trazodone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and trazodone due to the risk for additive CNS depression.
    Triazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Tricyclic antidepressants: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
    Trihexyphenidyl: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and trihexyphenidyl use. Concomitant use may result in additive anticholinergic adverse effects.
    Trospium: (Moderate) Dry mouth and drowsiness may occur in patients receiving cetirizine/levocetirizine; caution may be necessary during concomitant use of cetirizine/levocetirizine with the antimuscarinics.
    Valerian, Valeriana officinalis: (Moderate) Concurrent use of cetirizine/levocetirizine with valerian should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Valproic Acid, Divalproex Sodium: (Moderate) Concurrent use of cetirizine/levocetirizine with valproic acid should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
    Zaleplon: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and zaleplon due to the risk for additive CNS depression and next-day psychomotor impairment; dose adjustments may be necessary.
    Ziprasidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
    Zolpidem: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and zolpidem due to the risk for additive CNS depression and next-day psychomotor impairment; dose adjustments may be necessary. Limit the dose of Intermezzo sublingual tablets to 1.75 mg/day.

    PREGNANCY AND LACTATION

    Pregnancy

    There are no adequate or well-controlled studies with the use of cetirizine during human pregnancy. Animal studies do not reveal a risk for teratogenesis, even at doses greatly exceeding the maximum recommended daily human dose on mg/m2 basis; however, animal studies are not always predictive of human response. Use cetirizine during pregnancy only if the potential benefit justifies the potential risk to the fetus.[40967] [61987] Self-medication with cetirizine (nonprescription or OTC formulations) during pregnancy is not recommended. Pregnant patients should see their health care professional for a proper diagnosis and treatment recommendations. The American College of Obstetricians and Gynecologists and the American College of Allergy, Asthma, and Immunology consider cetirizine and loratadine as acceptable alternatives in pregnancy, preferably after the first trimester, when first-generation antihistamines are not tolerated.[46717]

    Cetirizine is excreted in human breast milk after oral administration. It is not known whether systemic absorption from the topical ocular administration of cetirizine could produce detectable quantities in breast milk. There is no adequate information regarding the effects of cetirizine on the breast-fed infant or the effects on milk production. Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for cetirizine and any potential adverse effects on the breast-fed child from cetirizine. The British Society for Allergy and Clinical Immunology recommends cetirizine at the lowest dose as a preferred antihistamine in breast-feeding women. Loratadine is also usually considered compatible with breast-feeding.

    MECHANISM OF ACTION

    Cetirizine has high affinity for histamine H1-receptors. It has less affinity, however, than terfenadine or hydroxyzine for calcium-channel, alpha-adrenergic, D2-dopamine, 5HT2-serotonin, and muscarinic receptors. In both atopic and normal human volunteers, cetirizine reduction of histamine wheal and flare is similar to that of clemastine, hydroxyzine, and terfenadine. The addition of the less lipophilic carboxyl group to the ethylamine side chain reduces the penetration of cetirizine into the CNS. Consequently, cetirizine produces a low incidence of sedation compared with older antihistamines. Drowsiness may, nevertheless, be dose-related.
     
    The inflammatory response involves a number of mediators. Initial release of histamine from mast cells is followed by late-phase reactions involving a number of other cells. These include fibroblasts and epithelial cells, neutrophils, eosinophils (especially in conditions with raised IgE levels), macrophages, platelets, and lymphocytes. Cell adhesion can also be part of the inflammatory process. The action of cetirizine appears to involve a number of these mediators. Cetirizine's effect on mast cells has generated conflicting reports. Some investigators found that cetirizine decreased prostaglandin D2, while others did not. Similarly, cetirizine may decrease leukotriene C4 production. Cetirizine plays a part in suppressing neutrophil migration in IgE-mediated reactions. Cetirizine reduces eosinophil infiltration to nasal mucosa in patients with seasonal allergic rhinitis. A similar effect is seen in patients with delayed-pressure urticaria. Cetirizine is not believed to affect the immune response, but it might affect cell adhesion. The mechanism of action may involve the inhibition of platelet-activating factor (PAF)-induced influx of eosinophils.

    PHARMACOKINETICS

    Cetirizine is administered orally, topically via the ophthalmic route, and as an intravenous injection. It is 93% protein-bound. Cetirizine undergoes a low degree of first-pass metabolism. It is metabolized to limited extent via O-dealkylation to a metabolite with negligible activity; the enzyme(s) responsible for metabolism have not been determined. Overall recovery of an administered dose is roughly 70% in the urine; approximately 50% of a dose is excreted as unchanged drug. Overall recovery from the feces is roughly 10%. The elimination half-life of cetirizine in healthy adult volunteers ranges 6.5 to 10 hours (mean 8.3 hours).
     
    Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: None

    Oral Route

    The bioavailability of cetirizine tablets and oral syrup is comparable. The drug has a rapid onset (i.e., time to Cmax 1 hour in adults) and a long duration of action. The overall bioavailability of cetirizine is not altered by the presence of food, although the rate of absorption can be slightly reduced.

    Other Route(s)

    Ophthalmic Route
    Peak plasma concentrations (Cmax) obtained after administration of cetirizine ophthalmic solution are significantly lower than those achieved by the oral formulations. In a study of healthy subjects, twice daily administration of the ophthalmic solution for 1 week resulted in a Cmax of 3.1 ng/mL. By comparison, the mean Cmax observed in healthy subjects receiving 10 mg tablets once daily for 10 days was 311 ng/mL. The mean terminal half-life was 8.2 hours after twice-daily dosing of ophthalmic cetirizine for 1 week.