Pharm

Cetirizine

search

Cetirizine, Zyrtec, Levocetirizine, Xyzal

  • See Also
  1. Second Generation Antihistamine
  2. Antihistamine
  3. Allergic Rhinitis
  • Indications
  1. Pruritus
  2. Allergic Rhinitis
    1. More rapid onset than other Non-Sedating Antihistamines (1 hour instead of 3 hours)
    2. Allows as needed dosing (such as for acute reactions, as allergists frequently used)
  • Mechanism
  1. Second Generation Antihistamine
  2. Cetirizine and Levocetirizine are analogs of the Sedating AntihistamineHydroxyzine
    1. Most sedating of the Non-Sedating Antihistamines (Second Generation Antihistamines)
  • Medications
  1. Cetirizine (Zyrtec)
    1. Available OTC in U.S. since 2007
    2. Tablets or chewables: 5-10 mg
    3. Syrup 5 mg/5 ml
  2. Levocetirizine (Xyzal)
    1. Active isomer of Cetirizine (Zyrtec), hence dosing is 50% of Cetirizine
  • Dosing
  • Cetirizine (Zyrtec)
  1. General
    1. FDA approved for perennial allergies in age >=6 months (seasonal allergies in age >=2 years)
    2. Allergists frequently prescribe Cetirizine in Allergic Reactions at higher dose and twice daily (off label use)
  2. Adult Dose (includes ages 6-11): 5 to 10 mg orally daily
  3. Child Dose (ages 2-5 years): 2.5 mg orally daily to twice daily
  4. Infant Dose (ages 6 months to 2 years): 2.5 mg orally daily
  5. Decrease dose in renal or hepatic Impairment
  • Dosing
  • Levocetirizine (Xyzal)
  1. FDA approved for age >=6 months
  2. Adult Dose (ages 12 and over): 5 mg orally daily
  3. Child Dose (ages 6-11 years): 2.5 mg orally daily
  • Safety
  1. Contraindicated in Lactation (Cetirizine and Levocetirizine)
  2. Pregnancy Class B agents (Cetirizine and Levocetirizine)
  • Adverse Effects
  1. See Antihistamine
  2. Drowsiness
    1. Although labeled as non-sedating, these Antihistamines may still cause sedation (esp. Cetirizine)
    2. May be sedating even at normally recommended doses (Hydroxyzine analog); reported by 10% of patients
  3. Severe systemic Pruritus on withdrawal
    1. Uncommon adverse effect after prolonged use (months to years), especially with Cetirizine
    2. Maximize use of Intranasal Corticosteroids and use Antihistamines as needed (instead of continuous)
    3. Chung (2019) Ther Adv Drug Saf 10:2042098619859996 +PMID: 31308927 [PubMed]
  • Resources
  1. Cetirizine Tablet (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b165db38-b302-4220-8627-77cb07bb078c
  2. Levocetirizine (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=717eb542-3a05-485e-be76-3930efb40d33
  • References
  1. Howarth (1999) J Allergy Clin Immunol 104:927 [PubMed]
  2. Walsh (2001) Drugs 61:207 [PubMed]
  3. (2001) Med Lett Drugs Ther 43(1103):35