Hydroxyzine

Hydroxyzine
Clinical data
Pronunciation	/haɪˈdrɒksɪziːn/
Trade names	Atarax, Vistaril, others
Other names	UCB-4492
AHFS/Drugs.com	Monograph
MedlinePlus	a682866
License data	US DailyMed: Hydroxyzine;
Dependence; liability	None
Routes of; administration	By mouth, intramuscular
Drug class	First-generation antihistamine
ATC code	N05BB01 (WHO) N05BB51 (WHO);
Legal status
Legal status	AU: S4 (Prescription only); CA: ℞-only; UK: POM (Prescription only); US: ℞-only; EU: Rx-only; In general: ℞ (Prescription only);
Pharmacokinetic data
Bioavailability	High
Protein binding	93%
Metabolism	Liver
Metabolites	Cetirizine, others
Elimination half-life	Adults: 20.0 hours; Elderly: 29.3 hours; Children: 7.1 hours
Excretion	Urine, feces
Identifiers
	IUPAC name (±)-2-(2-{4-[(4-chlorophenyl)-phenylmethyl]piperazin-1-yl}ethoxy)ethanol;
CAS Number	68-88-2 10246-75-0 (pamoate); as HCl: 2192-20-3;
PubChem CID	3658; as HCl: 91513;
IUPHAR/BPS	7199;
DrugBank	DB00557 ; as HCl: DBSALT000343;
ChemSpider	3531 ; as HCl: 82634;
UNII	30S50YM8OG; as HCl: 76755771U3;
KEGG	D08054 ; as HCl: D00672;
ChEBI	CHEBI:5818 ; as HCl: CHEBI:5819;
ChEMBL	ChEMBL896 ; as HCl: ChEMBL3186993;
CompTox Dashboard (EPA)	DTXSID8023137 ;
ECHA InfoCard	100.000.630
Chemical and physical data
Formula	C21H27ClN2O2
Molar mass	374.91 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES Clc1ccc(cc1)C(c2ccccc2)N3CCN(CC3)CCOCCO;
	InChI InChI=1S/C21H27ClN2O2/c22-20-8-6-19(7-9-20)21(18-4-2-1-3-5-18)24-12-10-23(11-13-24)14-16-26-17-15-25/h1-9,21,25H,10-17H2 ; Key:ZQDWXGKKHFNSQK-UHFFFAOYSA-N ;
	(verify)

Hydroxyzine, sold under the brand names Atarax and Vistaril among others, is an antihistamine medication. It is used in the treatment of itchiness, anxiety, insomnia, and nausea (including that due to motion sickness). It is used either by mouth or injection into a muscle.

Hydroxyzine works by blocking the effects of histamine. It is a first-generation antihistamine in the piperazine family of chemicals. Common side effects include sleepiness, headache, and dry mouth. Serious side effects may include QT prolongation. It is unclear if use during pregnancy or breastfeeding is safe.

It was first made by Union Chimique Belge in 1956 and was approved for sale by Pfizer in the United States later that year. In 2022, it was the 46th most commonly prescribed medication in the United States, with more than 13 million prescriptions.