Hydroxyzine

Antihistamine — NERVOUS SYSTEM

Key facts

Hydroxyzine is an ofp drug in the Antihistamine class catalogued in DrugCentral. It was first approved by the FDA in 1956. Its mechanism of action is classified as Histamine Receptor Antagonists. DrugCentral lists 6 molecular targets, including HRH1, HTR2A and DRD2. Recorded indications include Allergic conjunctivitis, Allergic rhinitis, Atopic dermatitis and Dermatographic urticaria.

• Approval status: ofp (first approved 1956 by the FDA).
• Drug class: Antihistamine.
• Mechanism of action: Histamine Receptor Antagonists.
• Molecular targets: HRH1, HTR2A, DRD2 and CYP2D6 (6 listed in DrugCentral).
• Indications: Allergic conjunctivitis, Allergic rhinitis, Atopic dermatitis, Dermatographic urticaria and Itching of skin and others.
• ATC code: N05BB01 (Diphenylmethane derivatives).
• Molecular formula: C21H27ClN2O2; molecular weight 374.91 g/mol.

Indications & contraindications

Drug–disease relationships curated by DrugCentral (OMOP / SNOMED concepts).

Indications (7)

• Allergic conjunctivitis
• Allergic rhinitis
• Atopic dermatitis
• Dermatographic urticaria
• Itching of skin
• Nasal discharge
• Urticaria

Off-label uses (1)

• Severe Pruritus

Contraindications (37)

• Acute hepatitis
• Alcoholism
• Angina pectoris
• Angle-closure glaucoma
• Benign prostatic hyperplasia
• Bladder outflow obstruction
• Chronic heart failure
• Chronic idiopathic constipation
• Chronic myocardial ischemia
• Conduction disorder of the heart
• Continuous fever
• Cor pulmonale
• Cystic fibrosis
• Diabetes mellitus
• Disease of liver
• Disorder of cardiovascular system
• Disorder of coronary artery
• Hypertensive disorder
• Hyperthyroidism
• Hypothyroidism
• Multiple organ failure
• Myocardial infarction
• Myocardial ischemia
• Open-angle glaucoma
• Peptic ulcer
• Psychotic disorder
• Pulmonary edema
• Retention of urine
• Seizure disorder
• Sepsis syndrome
• + 7 more

Mechanism & targets

• Mechanism of action (MoA): Histamine Receptor Antagonists
• Established pharmacologic class: Antihistamine

Molecular targets (6)

Target	Gene	Action	Activity
Histamine H1 receptor	HRH1	antagonist	Ki 8.70
5-hydroxytryptamine receptor 2A	HTR2A	unknown	Ki 7.30
D(2) dopamine receptor	DRD2	unknown	Ki 6.42
Cytochrome P450 2D6	CYP2D6	unknown	Ki 5.41
Envelope glycoprotein gp160	env	unknown	IC50 5.20
Envelope glycoprotein gp160 [Cleaved into: Surface protein gp120	env	unknown	IC50 5.20

Regulatory approvals (1)

Date	Agency	Marketed as	Applicant	Orphan
1956-04-12	FDA	—	PFIZER

ATC classification

ATC code	Therapeutic hierarchy
N05BB01	NERVOUS SYSTEM › PSYCHOLEPTICS › ANXIOLYTICS › Diphenylmethane derivatives
N05BB51	NERVOUS SYSTEM › PSYCHOLEPTICS › ANXIOLYTICS › Diphenylmethane derivatives

Reported adverse-event signals

Strongest FDA FAERS disproportionality signals (log-likelihood ratio). A signal is a statistical association in spontaneous reports, not proof that the drug causes the event.

MedDRA term	LLR
Completed suicide	3139.0
Toxicity to various agents	1676.3
Dermatitis atopic	1121.6
Intentional overdose	974.0
Drug abuse	958.2
Pruritus	842.6
Intentional self-injury	491.5
Suspected suicide	383.2
Synovitis	369.1
Cardio-respiratory arrest	361.1
Suicide attempt	358.1
Pemphigus	348.4

Chemical structure

Full physicochemical, ADMET and 3D-structure analysis of Hydroxyzine is on its molecule page.

• Molecular formula: C₂₁H₂₇ClN₂O₂
• Molecular weight: 374.91 g/mol
• CAS number: —
• InChIKey: ZQDWXGKKHFNSQK-UHFFFAOYSA-N
• PubChem CID: 3658

OCCOCCN1CCN(CC1)C(C1=CC=CC=C1)C1=CC=C(Cl)C=C1

Frequently asked questions

Answers are generated from the structured data on this page, not written by hand.

What is Hydroxyzine used for?

DrugCentral lists the following indications for Hydroxyzine: Allergic conjunctivitis, Allergic rhinitis, Atopic dermatitis, Dermatographic urticaria, Itching of skin, Nasal discharge and Urticaria.

How does Hydroxyzine work?

Hydroxyzine is classified as Histamine Receptor Antagonists; its molecular targets in DrugCentral include HRH1 (antagonist), HTR2A, DRD2 and CYP2D6.

When was Hydroxyzine first approved?

Hydroxyzine was first approved by the FDA in 1956.

What drug class does Hydroxyzine belong to?

Hydroxyzine is in the Antihistamine class.

What is the chemical formula of Hydroxyzine?

Hydroxyzine has the molecular formula C21H27ClN2O2 and a molecular weight of 374.91 g/mol.

Sources

• DrugCentral drug card 1400 — structure, indications, targets, approvals, pharmacologic classes (CC BY-SA 4.0)
• ChEMBL CHEMBL1200467 — compound record and bioactivity
• PubChem CID 3658 — chemical identifiers
• DrugBank DB00557 — drug record
• FDA UNII 30S50YM8OG — substance identity
• DailyMed: FDA labels for Hydroxyzine — current prescribing information (label search)
• UniProt P35367 (HRH1) — target protein
• UniProt P28223 (HTR2A) — target protein
• UniProt P14416 (DRD2) — target protein
• UniProt P10635 (CYP2D6) — target protein
• FDA Adverse Event Reporting System (openFDA FAERS) — adverse-event signals, as aggregated by DrugCentral

How this page is built: methodology · editorial policy & corrections.