From Simple English Wikipedia, the free encyclopedia
Cetirizine structure.svg
Clinical data
Trade namesZyrtec, Incidal, others
License data
  • AU: B2
Routes of
By mouth
ATC code
Legal status
Legal status
Pharmacokinetic data
BioavailabilityWell-absorbed (>70%)[3]
Protein binding88–96%[3]
MetabolismMinimal (non-cytochrome P450-mediated)[1][2]
Onset of action20–42 minutes[2]
Elimination half-lifeMean: 8.3 hours[1][2]
Range: 6.5–10 hours[4]
Duration of action≥24 hours[4]
ExcretionUrine: 70–85%[1]
Feces: 10–13%[1]
  • (±)-[2-[4-[(4-Chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid
CAS Number
PubChem CID
ECHA InfoCard100.223.545 Edit this at Wikidata
Chemical and physical data
Molar mass388.89 g·mol−1
3D model (JSmol)
  • Clc1ccc(cc1)C(c2ccccc2)N3CCN(CC3)CCOCC(=O)O
  • InChI=1S/C21H25ClN2O3/c22-19-8-6-18(7-9-19)21(17-4-2-1-3-5-17)24-12-10-23(11-13-24)14-15-27-16-20(25)26/h1-9,21H,10-16H2,(H,25,26) checkY

Cetirizine, sold under the brand name Zyrtec and others, is an antihistamine medication used to treat allergies. It is taken by mouth. It starts working within an hour and it lasts for about a day.[5] It works as well as other antihistamines like diphenhydramine.[6]

Common side effects are sleepiness, dry mouth, headache, and a abdominal pain.[6] There is less sleepiness than in first generation antihistamines.[5] Pregnant women can use it, but not women who are breastfeeding.[7] It works by blocking histamine at H1 receptors, mostly outside of the brain.[6]

It was patented in 1981, and was first used in 1987.[8][9] It is on the World Health Organization's List of Essential Medicines.[10] It is available as a generic medication.[5] It was the 67th most commonly prescribed medication in the United States in 2019, with over 11 million prescriptions.[11][12]

References[change | change source]

  1. 1.0 1.1 1.2 1.3 Portnoy JM, Dinakar C (2004). "Review of cetirizine hydrochloride for the treatment of allergic disorders". Expert Opin Pharmacother. 5 (1): 125–35. doi:10.1517/14656566.5.1.125. PMID 14680442. S2CID 28946859.
  2. 2.0 2.1 2.2 Simons FE, Simons KJ (1999). "Clinical pharmacology of new histamine H1 receptor antagonists". Clin Pharmacokinet. 36 (5): 329–52. doi:10.2165/00003088-199936050-00003. PMID 10384858. S2CID 21360079.
  3. 3.0 3.1 Chen C (2008). "Physicochemical, pharmacological and pharmacokinetic properties of the zwitterionic antihistamines cetirizine and levocetirizine". Curr. Med. Chem. 15 (21): 2173–91. doi:10.2174/092986708785747625. PMID 18781943.
  4. 4.0 4.1 Simons FE (2002). "Comparative pharmacology of H1 antihistamines: clinical relevance". Am. J. Med. 113 Suppl 9A (9): 38S–46S. doi:10.1016/s0002-9343(02)01436-5. PMID 12517581.
  5. 5.0 5.1 5.2 British national formulary : BNF 76 (76 ed.). Pharmaceutical Press. 2018. p. 279. ISBN 9780857113382.
  6. 6.0 6.1 6.2 "Cetirizine Hydrochloride Monograph for Professionals". Drugs.com. American Society of Health-System Pharmacists. Retrieved 3 March 2019.
  7. "Cetirizine Pregnancy and Breastfeeding Warnings". Drugs.com. Retrieved 3 March 2019.
  8. Fischer, Jnos; Ganellin, C. Robin (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 549. ISBN 9783527607495.
  9. US patent 4525358, Baltes E, De Lannoy J, Rodriguez L, "2-[4-(Diphenylmethyl)-1-piperazinyl]-acetic acids and their amides", issued 25 June 1985, assigned to UCB Pharmaceuticals, Inc. 
  10. World Health Organization (2021). World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. hdl:10665/345533. WHO/MHP/HPS/EML/2021.02.
  11. "The Top 300 of 2019". ClinCalc. Retrieved 16 October 2021.
  12. "Cetirizine - Drug Usage Statistics". ClinCalc. Retrieved 16 October 2021.