Hydroxyzine

證據等級: L5

預測適應症: 5 個

Hydroxyzine: From Antihistamine/Antipruritic Use to Allergic Urticaria

One-Sentence Summary

Hydroxyzine is a first-generation H1-antihistamine historically used for allergic and pruritic conditions (as reflected in the literature evidence collected here). The TxGNN model predicts it may be effective for Allergic Urticaria, with 1 clinical trial and 20 publications currently identified, though most of this literature centers on related second-generation antihistamines (cetirizine, levocetirizine) rather than hydroxyzine directly.

Quick Overview

Item	Content
Original Indication	Not available from regulatory license data (drug currently unlicensed in this market); literature in this pack identifies hydroxyzine as a first-generation H1-antihistamine used for allergic/pruritic conditions
Predicted New Indication	Allergic Urticaria
TxGNN Prediction Score	99.77%
Evidence Level	L3
US Market Status	✗ Not Marketed
Number of NDAs	0
Recommended Decision	Research Question

Why is This Prediction Reasonable?

Detailed mechanism-of-action data is not currently available for hydroxyzine (flagged as a High-severity data gap, DG002). Based on the literature evidence collected, hydroxyzine is a first-generation H1 histamine receptor antagonist; cetirizine, one of its well-known carboxylated metabolites, is explicitly noted in PMID 1981354 and PMID 11034010 as being derived from hydroxyzine.

Allergic urticaria is mediated by mast-cell histamine release causing the classic wheal-and-flare reaction, which is the direct pharmacological target of H1-receptor blockade. Multiple reviews in this evidence set (PMID 31582993, PMID 28913986) explicitly note that hydroxyzine has historically been used alongside diphenhydramine as a first-generation antihistamine option for chronic and allergic urticaria, though current guidelines favor newer, less-sedating second-generation agents as first-line therapy due to a more favorable safety profile.

Mechanistically, the prediction is reasonable and consistent with hydroxyzine’s known antihistaminic pharmacology. However, the clinical trial and literature evidence gathered for this specific candidate predominantly involves related but distinct molecules (cetirizine, levocetirizine, bilastine, desloratadine) rather than head-to-head data on hydroxyzine itself in allergic urticaria — this is an indirect, class-based evidentiary link rather than a direct one.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT02023164	Phase 3	Completed	36	Multicenter pilot study comparing IV cetirizine injection (10 mg) to IV diphenhydramine (50 mg) for acute urticaria in emergency/urgent-care settings. Note: relevance graded “C” — the tested drug is cetirizine, not hydroxyzine, so this is only an indirect, same-class reference.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
31582993	2019	Position Statement/Review	Allergy Asthma Clin Immunol	CSACI position statement — explicitly names hydroxyzine (with diphenhydramine) as a first-generation antihistamine historically used for urticaria, but recommends newer agents as safer first-line therapy
28913986	2017	Review	Allergy Asthma Immunol Res	Chronic spontaneous urticaria treatment review; notes hydroxyzine (Atarax) and diphenhydramine were historically used at high doses before step-up to omalizumab
1981354	1990	Review	Drugs	Review of cetirizine, described as a piperazine derivative and carboxylated metabolite of hydroxyzine, in allergic rhinitis and chronic urticaria
16278258	2005	Review	Ann Pharmacother	Review of oral antihistamine efficacy/safety for allergic rhinitis and chronic idiopathic urticaria
11034010	2000	Case Report	J Clin Gastroenterol	Case of cetirizine-induced cholestasis; notes cetirizine is a human metabolite of hydroxyzine, approved for chronic urticaria
12113226	2002	Review	Clin Allergy Immunol	Review of H1-antihistamines in children, including allergic conditions
18336052	2008	Review	Clin Pharmacokinet	Comparative pharmacokinetics/pharmacodynamics of desloratadine, fexofenadine, and levocetirizine in allergic rhinitis and chronic idiopathic urticaria
22686617	2012	Review	Drugs	Bilastine review in allergic rhinitis and urticaria
18201439	2007	Review	Allergy Asthma Proc	Levocetirizine as a treatment option for allergic rhinitis and chronic idiopathic urticaria
19808127	2009	Review	Clin Ther	Levocetirizine for allergic rhinitis and chronic idiopathic urticaria in adults and children

US Market Information

No marketing authorization records are available in this evidence pack — hydroxyzine’s regulatory status is recorded as “未上市” (not marketed), with 0 licenses on file.

Safety Considerations

Please refer to the package insert for safety information. (Key warnings, contraindications, and drug-interaction data were not retrievable at the time of this evaluation — flagged as Blocking data gap DG001.)

Conclusion and Next Steps

Decision: Research Question

Rationale: The H1-antagonist mechanism is pharmacologically plausible for allergic urticaria, and hydroxyzine is already referenced in the literature as historically used for this class of condition. However, the specific evidence assembled here (1 low-relevance Phase 3 trial, 20 reviews mostly about other antihistamines) does not directly establish efficacy for hydroxyzine itself in allergic urticaria — it does not yet meet the bar for a Go or even a guarded Proceed decision.

To proceed, the following is needed:

TFDA/regulatory label warnings and contraindications (Blocking gap, DG001)
Confirmed mechanism-of-action data from DrugBank (High-priority gap, DG002)
Direct clinical evidence (trials or studies) evaluating hydroxyzine specifically — not related metabolites — in allergic urticaria
Drug-drug interaction data, currently unresolved (query status: not found)
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.