II. Indications
-
Allergic Rhinitis
- More rapid onset than other Non-Sedating Antihistamines (1 hour instead of 3 hours)
- Allows as needed dosing (such as for acute reactions, as allergists frequently used)
- More rapid onset than other Non-Sedating Antihistamines (1 hour instead of 3 hours)
III. Mechanism
- Second Generation Antihistamine
- Cetirizine and Levocetirizine are analogs of the Sedating AntihistamineHydroxyzine
- Most sedating of the Non-Sedating Antihistamines (Second Generation Antihistamines)
IV. Dosing: Cetirizine (Zyrtec)
- FDA approved for perennial allergies in age >=6 months (seasonal allergies in age >=2 years)
- Allergists frequently prescribe Cetirizine in Allergic Reactions at higher dose and twice daily (off label use)
- Available OTC in U.S. since 2007
- Tablets or chewables: 5-10 mg
- Syrup 5 mg/5 ml
- Adult Dose (includes ages 6-11): 5 to 10 mg orally daily
- Child Dose (ages 2-5 years): 2.5 mg orally daily to twice daily
- Infant Dose (ages 6 months to 2 years): 2.5 mg orally daily
- Decrease dose in renal or hepatic Impairment
V. Dosing: Levocetirizine (Xyzal)
- Active isomer of Cetirizine (Zyrtec), hence dosing is 50% of Cetirizine
- FDA approved for age >=6 months
- Adult Dose (ages 12 and over): 5 mg orally daily
- Child Dose (ages 6-11 years): 2.5 mg orally daily
VI. Safety
- Contraindicated in Lactation (Cetirizine and Levocetirizine)
- Pregnancy Class B agents (Cetirizine and Levocetirizine)
VII. Adverse Effects
- See Antihistamine
- Drowsiness
- Although labeled as non-sedating, these Antihistamines may still cause sedation (esp. Cetirizine)
- May be sedating even at normally recommended doses (Hydroxyzine analog); reported by 10% of patients
VIII. References
- Howarth (1999) J Allergy Clin Immunol 104:927 [PubMed]
- Walsh (2001) Drugs 61:207 [PubMed]
- (2001) Med Lett Drugs Ther 43(1103):35
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Related Studies
| cetirizine (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| CETIRIZINE HCL 1 MG/ML SOLN | Generic | $0.02 per ml |
| CETIRIZINE HCL 1 MG/ML SYRUP | Generic | $0.02 per ml |
| CETIRIZINE HCL 10 MG CHEW TAB | Generic OTC | $1.79 each |
| CETIRIZINE HCL 10 MG TABLET | Generic OTC | $0.07 each |
| CETIRIZINE HCL 5 MG CHEW TAB | Generic OTC | $1.93 each |
| CETIRIZINE HCL 5 MG TABLET | Generic OTC | $0.05 each |
| CETIRIZINE-PSE ER 5-120 MG TAB | Generic OTC | $0.62 each |
| levocetirizine (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| LEVOCETIRIZINE 2.5 MG/5 ML SOL | Generic | $0.17 per ml |
| LEVOCETIRIZINE 5 MG TABLET | Generic | $0.07 each |