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loratadine (Clarityn RediTabs / Claritin Reditabs / loratadine, Zydis)

✓ Approved

Merck & Co. · HRH1 · Small Molecule

What is loratadine?

loratadine is a small molecule developed by Merck & Co.. It is approved for therapeutic indications via oral (po).

Drug Profile

Brand NamesClarityn RediTabs, Claritin Reditabs, loratadine, Zydis
CompanyMerck & Co.
Drug ClassSmall Molecule
Molecular TargetHRH1
RouteOral (PO)
StatusApproved
Sources: ClinicalTrials.gov, Merck & Co.

Mechanism of Action

Molecular Targets

loratadine acts on 1 molecular target:

HRH1histamine receptor H1 (HH1R, H1R)
Want deeper analysis?Noah AI can explain complex mechanisms and compare to similar drugs.

Therapeutic Indications

loratadine is developed for 2 unique indications across 2 therapeutic areas.

Therapeutic AreaConditionPhase
Respiratory, thoracic and mediastinal disordersRhinitis allergic✓ Approved
Skin and subcutaneous tissue disordersUrticaria✓ Approved

Related Research Articles

PubMedInternational journal of molecular sciences2026-10-16

Unveiling Novel Molecular Candidate Targets of Loratadine, Raloxifene, and Sorafenib in Hepatocellular Carcinoma.

Villarruel-Melquiades Fernanda F, Noyola-Díaz Martha M, Martínez-Gudiño Gelacio G, Mendoza-Garrido María Eugenia ME et al.

Hepatocellular carcinoma (HCC) remains a major global health burden. We have recently demonstrated the synergistic cytotoxicity elicited by the combination of loratadine, raloxifene, and sorafenib in liver cancer cells. In this study, we investigated the potential mechanistic basis of this novel multi-drug regimen by identifying candidate protein targets of the three drugs. Potential protein targets of each drug were identified using the Drug Affinity Responsive Target Stability (DARTS) assay in protein extracts from the HCC cell line HuH7, and molecular docking was performed to predict binding modes and explore the structural feasibility of these drug-target interactions. Bioinformatics analyses were conducted to predict biological functions, molecular interactions, and clinical relevance. We identified 147 potential candidate DARTS-stabilized proteins for loratadine, 191 for sorafenib, and 157 for raloxifene; a proportion of these candidate proteins maintained a statistically significant association with overall survival in HCC patients: 20.14% for loratadine, 22.93% for raloxifene, and 24.47% for sorafenib. Cross-referencing with public databases confirmed several previously documented targets-complementing our experimental approach-while revealing numerous previously unreported target candidates. Docking analyses predicted favorable binding interactions between the drugs and several proteins, such as the putative complex between loratadine and N-glycanase 1 (NGLY1), whose expression correlates with reduced overall survival in HCC patients. Functional enrichment analysis showed that several targets are involved in hallmarks of cancer. Clinically relevant candidate targets of loratadine, raloxifene, and sorafenib were identified. However, as these candidate protein targets were identified exclusively in HuH7 cells, they may not fully generalize across all HCC models without further validation. Nevertheless, our results suggest that loratadine, raloxifene and sorafenib modulate key pathways involved in tumorigenesis. These findings strengthen the use of this combination as a promising therapeutic strategy for HCC and provide new opportunities for the identification of novel targets, prognostic markers, and molecular vulnerabilities suitable for pharmacological intervention in HCC and other malignancies and diseases.

PMID 42883895
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PubMedFrontiers in medicine2026-10-13

Vitiligo developing during dupilumab treatment in a child with atopic dermatitis: a case report and literature review.

Yu Peng P, Wei Fenglei F

An 8-year-11-month-old girl with severe atopic dermatitis had previously received treatments including topical hydrocortisone butyrate, pimecrolimus, tacrolimus, hormone ointment encapsulation, and narrowband ultraviolet B (NB-UVB) phototherapy. She also took oral antihistamines such as cetirizine and loratadine, but these interventions provided limited relief, and her pruritus persisted. In August 2023, she began dupilumab therapy with a 400 mg subcutaneous loading dose, followed by 200 mg subcutaneous injections every two weeks. Vitiligo developed three months after dupilumab initiation in this child with severe atopic dermatitis and improved with combination therapy while dupilumab was continued. Together with previously published reports, this observation supports a possible temporal association between dupilumab exposure and vitiligo development; however, causality cannot be established from the currently available evidence.

PMID 42865691
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PubMedWater research2026-10-08

Effect-directed analysis combined with machine learning and QSAR prioritization identifies major estrogen receptor agonists in industrialized coastal sediments.

Gwak Jiyun J, Lee Songyeon S, Cha Jihyun J, Kim Taewoo T et al.

Estrogen receptor (ER)-mediated activity in sediments remains insufficiently characterized due to unidentified ER-active compounds that may not be captured by targeted analysis and complex agonistic/antagonistic interactions in environmental mixtures. This study applied an integrated framework combining effect-directed analysis, nontarget screening, machine learning, and quantitative structure-activity relationship (QSAR) modeling to identify major ER agonists in sediments from Lake Sihwa, a highly industrialized coastal system in South Korea. ER-mediated activity, measured using the T47D-Kbluc bioassay, was detected at all sites and was mainly associated with the polar fraction and its reversed-phase high-performance liquid chromatography subfraction, particularly in industrial inland creeks. Sediment-associated ER activity frequently exceeded effect-based trigger values (3.6 × 10-1 ngE2 g-1OC for freshwater sediments and 1.8 × 10-1 ngE2 g-1OC for marine sediments), indicating widespread estrogenic risk. However, four target ER agonists (estrone, 17β-estradiol, arenobufagin, and loratadine) accounted for only 10-53% of the observed activity. A stepwise prioritization workflow integrating activity-guided filtering, descriptor-based machine learning, and VEGA QSAR prediction reduced more than 15,000 detected features to a small number of candidate compounds. Diethylstilbestrol (DES) and heptyl paraben were newly identified as contributors to sediment-associated ER-mediated activity. DES exhibited high estrogenicity (relative potency = 1.5 with E2) and accounted for up to 28% of the observed activity, indicating that it is a major contributor to sediment-associated estrogenicity. These findings suggest that persistent synthetic estrogens may represent previously overlooked drivers of estrogenic effects in contaminated sediments.

PMID 42849407
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PubMedBiomedicines2026-09-26

Rewiring of Molecular Networks Induced by the Combination of Loratadine, Raloxifene, and Sorafenib Leads to the Identification of Clinically Relevant Therapeutic Targets in Hepatocellular Carcinoma.

Villarruel-Melquiades Fernanda F, Santos-Martínez Nancy N, Noyola-Díaz Martha M, Terán-Sánchez Estefanía de Jesús EJ et al.

Background/Objectives: Hepatocellular carcinoma (HCC) is the most prevalent primary liver tumor and is often diagnosed at advanced stages with very poor therapeutic response, leading to high mortality. Thus, new therapeutic strategies and biomarkers are urgently needed. We previously showed that the combination of loratadine, raloxifene, and sorafenib exerts synergistic cytotoxicity on HCC cells. Here, we explored potential molecular mechanisms underlying the anticancer effects of this combination using multiomics analyses. Methods: We performed proteomic analyses based on mass spectrometry, transcriptomic analyses using the Clariom D Plus human microarray (Affymetrix), and metabolomic analyses based on nuclear magnetic resonance to investigate the profile changes induced by the drug combination in HuH7 cells. Bioinformatic analyses were applied to associate the omics changes with biological functions, molecular interactions, and clinical relevance in terms of patient survival. Results: We identified several molecules whose expression changed in response to treatment across the three omics profiles analyzed. Some of them were found to be involved in hallmarks of cancer, including sustained proliferation, evasion of growth suppressors, and resistance to cell death. Integrated multi-omics analyses revealed that the drug combination suppresses critical oncogenic drivers (C7orf50, NUP188, and HS2ST1) and that the mitotic cell cycle process, DNA synthesis and cholesterol biosynthesis are the primary pathways affected. Protein-protein interaction analysis revealed five key hubs (KIF2C, PCNA, TRIP13, NDC80, and RPA3), whose expression in HCC is associated with poor clinical prognosis. Conclusions: The combined treatment rewired molecular networks involved in HCC progression. These findings identify clinically relevant molecular targets associated with poor prognosis and provide mechanistic insights into the synergistic anticancer activity of this drug combination.

PMID 42792641
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PubMedFrontiers in microbiology2026-09-03

Effect of Xiaoqinglong decoction on gut-lung axis microbiota in allergic rhinitis mice.

Zhang Jie J, Zhou Si S, Liu Liang-Jing LJ, Mao Xiao-Ling XL et al.

This study aimed to characterize the effects of Xiaoqinglong decoction (XQLD) on the microbiota of the gut-lung axis at three key sites-the nasal cavity, lungs, and gut-in Allergic rhinitis (AR) mice, with particular attention to site-specific response patterns and their potential links to AR disease resolution. An ovalbumin-induced AR mouse model was established, with mice assigned to control, AR, loratadine, and XQLD groups. Intervention outcomes were assessed via behavioral observation, ELISA, histopathology, and 16S rRNA gene sequencing, followed by correlation analysis. Compared with the AR group, XQLD significantly reduced nasal symptoms, serum OVA-sIgE and IL-4 levels, and nasal mucosal injury. AR induction markedly altered the nasal and gut microbiota, whereas the lung microbiota remained relatively stable. XQLD significantly increased nasal Oxalobacteraceae and significantly decreased gut Rikenellaceae and Odoribacter. Gut Lactobacillaceae, Lactobacillus, and Allobaculum showed upward trends, whereas Helicobacter showed a slight downward trend. Several nasal and gut taxa were significantly associated with nasal symptoms and Th2-related inflammatory indicators. XQLD differentially modulates the gut-lung axis microbiota in AR mice, with the most marked changes observed in the gut, which may correlate with its therapeutic effects and merit further mechanistic exploration.

PMID 42688477
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PubMedFrontiers in medicine2026-08-28

Second-generation H1 antihistamines for the treatment of chronic urticaria: a network meta-analysis.

Li Zixuan Z, Zhang Juan J, Zheng Yaqi Y, Zhang Mingyan M et al.

To evaluate the efficacy and safety of 10 commonly used second-generation H1 antihistamines (cetirizine, levocetirizine, loratadine, desloratadine, ebastine, bilastine, olopatadine, rupatadine, fexofenadine, and mizolastine) at licensed doses in treating chronic urticaria using network meta-analysis. Seven electronic databases were searched, including PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, and Chinese Biomedical Literature Service System. Relevant literature from inception to the end of December 2025 was retrieved. Studies meeting the criteria were selected, and network meta-analysis was performed using Stata 16 software. A total of 54 studies involving 7,290 patients were included. Network meta-analysis indicated that olopatadine, mizolastine, bilastine, and levocetirizine were more effective than placebo in improving total symptom scores. All 10 drugs were superior to placebo in reducing itching scores, although only fexofenadine achieved statistical significance. For reducing wheal scores, ebastine was significantly more effective than mizolastine and loratadine. Regarding adverse reactions, no significant differences were observed between any of the drugs and placebo, with fexofenadine having the lowest adverse reaction rate. Sensitivity analyses excluding highrisk studies confirmed the robustness of findings across all outcomes. Based on current evidence, olopatadine at licensed dose exhibited the best efficacy in reducing total symptom scores. Fexofenadine was most effective for improving itching scores and ebastine was optimal for reducing wheal scores. In addition, fexofenadine had the lowest incidence of adverse reactions. However, the conclusions of this study still need to be validated by further high-quality randomized controlled trials.

PMID 42662818
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