Levocetirizine

Levocetirizine
Clinical data
Trade names	Xyzal, Levazyr, others
Other names	Levocetirizine dihydrochloride
AHFS/Drugs.com	Monograph
MedlinePlus	a607056
License data	US DailyMed: Levocetirizine;
Routes of; administration	By mouth
Drug class	Second generation antihistamines
ATC code	R06AE09 (WHO) ;
Legal status
Legal status	UK: POM (Prescription only); US: OTC / Rx-only;
Pharmacokinetic data
Bioavailability	High
Protein binding	91–92%
Metabolism	Minimal (less than 14%, primarily CYP3A4)
Elimination half-life	8 to 9 hours
Excretion	Urine: 85%; Feces: 12.9%
Identifiers
	IUPAC name 2-(2-{4-[(R)-(4-Chlorophenyl)(phenyl)methyl]piperazin-1-yl}ethoxy)acetic acid;
CAS Number	130018-77-8 ;
PubChem CID	1549000;
IUPHAR/BPS	1214;
DrugBank	DB06282 ;
ChemSpider	1266001 ;
UNII	6U5EA9RT2O;
KEGG	D07402 ; as salt: D08118 ;
ChEBI	CHEBI:94559;
ChEMBL	ChEMBL1201191 ;
PDB ligand	LCR (PDBe, RCSB PDB);
CompTox Dashboard (EPA)	DTXSID60156294 ;
Chemical and physical data
Formula	C21H25ClN2O3
Molar mass	388.89 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES Clc1ccc(cc1)[C@H](N2CCN(CCOCC(=O)O)CC2)c3ccccc3;
	InChI 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)/t21-/m1/s1 ; Key:ZKLPARSLTMPFCP-OAQYLSRUSA-N ;
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Levocetirizine, sold under the brand name Xyzal, among others, is a second-generation antihistamine used for the treatment of allergic rhinitis (hay fever) and long-term hives of unclear cause. It is less sedating than older antihistamines. It is taken by mouth.

Common side effects include sleepiness, dry mouth, cough, vomiting, and diarrhea. Use in pregnancy appears safe but has not been well studied and use when breastfeeding is of unclear safety. It is classified as a second-generation antihistamine and works by blocking histamine H₁-receptors.

Levocetirizine was approved for medical use in the United States in 2007, and is available as a generic medication. In 2022, it was the 152nd most commonly prescribed medication in the United States, with more than 3 million prescriptions.