Pharm

Cetirizine

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Cetirizine, Zyrtec, Levocetirizine, Xyzal

  • 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
  • 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