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Non-Sedating Antihistamine

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Non-Sedating Antihistamine, Second Generation Antihistamine, Loratadine, Claritin, Cetirizine, Zyrtec, Fexofenadine, Allegra

  • See Also
  1. Antihistamine
  • Indications
  1. Allergic Rhinitis
  • Pathophysiology
  1. Second Generation Antihistamine
  • Preparations
  • Advantages and Disadvantages
  1. Fexofenadine (Allegra)
    1. Least sedating, even in higher doses
  2. Loratadine (Claritin)
    1. Sedating at higher doses
    2. Less potent than Allegra and Zyrtec
  3. Cetirizine (Zyrtec) and Levocetirizine (Xyzal)
    1. May be sedating even at normally recommended doses (Hydroxyzine analog); reported by 10% of patients
    2. More rapid onset than other Non-Sedating Antihistamines (1 hour instead of 3 hours)
      1. Only significant if Antihistamine is taken as needed (instead of daily)
  • Preparations
  • Oral by Age Restrictions
  1. Age 6 months and older
    1. Cetirizine (Zyrtec, Pregnancy category B)
    2. Desloratadine (Clarinex, Pregnancy category C)
    3. Fexofenadine (Allegra, Pregnancy category C)
  2. Age 2 years and older
    1. Loratadine (Claritin, Pregnancy category B)
  3. Age 12 years and older
    1. Levocetirizine (Xyzal, Pregnancy category B)
  • Preparations
  • Oral
  1. Fexofenadine (Allegra, OTC, Tabs 30-60-180 mg, Dissolving 30 mg, Suspension 30 mg/5ml)
    1. Adult Dose (ages 12 and over): 60 mg orally twice daily or 180 mg orally daily
    2. Child Dose (ages 6-11 years): 30 mg orally twice daily
    3. Low sedation and highly effective
  2. Loratadine (Claritin, OTC, tabs 10 mg, Dissolving 5-10 mg, Syrup 1mg/ml)
    1. Adult Dose (ages 6 and over): 10 mg orally daily
    2. Child Dose (ages 2-5 years): 5 mg orally daily
  3. Cetirizine (Zyrtec, OTC, Tabs or Chewables 5-10 mg, Syrup 5 mg/5 ml)
    1. Adult Dose (includes ages 6-11): 5 or 10 mg orally daily
    2. Child Dose (ages 2-5 years): 2.5 mg orally daily to twice daily
    3. Infant Dose (ages 6 months to 2 years): 2.5 mg orally daily
  4. Levocetirizine (Xyzal, OTC, Scored Tabs 5 mg, solution 2.5 mg/5ml)
    1. Active isomer of Cetirizine (Zyrtec)
    2. Adult Dose (ages 12 and over): 5 mg orally daily
    3. Child Dose (ages 6-11 years): 2.5 mg orally daily
  5. Desloratadine (Clarinex, prescription only, tabs 5 mg, Dissolving 2.5-5 mg, Syrup 0.5 mg/ml)
    1. Adult Dose (ages 12 and over): 5 orally daily
    2. Child Dose (ages 6-11 years): 2.5 mg orally daily to twice daily
    3. Preschool Dose (ages 12 months to 5 years): 1.25 mg orally daily
    4. Infant Dose (ages 6-12 months): 1 mg orally daily
  • Preparations
  • Nasal
  1. Azelastine (Astelin) 1-2 sprays per nostril twice daily (ages 5 and over)
  2. Olopatadine (Patanol) 2 sprays per nostril twice daily (ages 12 and over)
  1. Contraindicated in Lactation
  2. Pregnancy Class B agents (other agents are Category C)
    1. Cetirizine (Zyrtec)
    2. Loratadine (Claritin)
    3. Levocetirizine (Xyzal)
  3. Pregnancy Class C agents
    1. Fexofenadine (Allegra)
      1. Appears as safe in pregnancy as other Non-Sedating Antihistamines that are category B (Cetirizine, Loratadine)
      2. Andersson (2020) JAMA Pediatr 174(8): e201316 [PubMed]
  • Drug Interactions
  1. Historical Only: Astemizole (Hismanal) and Terfenadine (Seldane)
    1. Prolong QT Interval
    2. Contraindicated with Erythromycin, Ketoconazole
    3. Resulted in fatal Arrhythmias in multiple cases
  2. Fexofenadine
    1. Absorption decreased by orange juice, Grapefruit juice, apple juice (separate by at least 4 hours)
  • 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