Katagiri F, Hatoyama-Tanaka S, Watanabe T, Takayanagi R, Suzuki M, Yamada Y. Effects of olopatadine hydrochloride on substance P concentrations in nasal secretions and nasal symptoms. World J Exp Med 2026; 16(1): 116584 [DOI: 10.5493/wjem.v16.i1.116584]
Corresponding Author of This Article
Fumihiko Katagiri, PhD, Lecturer, Department of Clinical Evaluation of Drug Efficacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan. katagiri@toyaku.ac.jp
Research Domain of This Article
Allergy
Article-Type of This Article
Clinical Trials Study
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This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Mar 20, 2026 (publication date) through Mar 20, 2026
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Journal Information of This Article
Publication Name
World Journal of Experimental Medicine
ISSN
2220-315x
Publisher of This Article
Baishideng Publishing Group Inc, 7041 Koll Center Parkway, Suite 160, Pleasanton, CA 94566, USA
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Katagiri F, Hatoyama-Tanaka S, Watanabe T, Takayanagi R, Suzuki M, Yamada Y. Effects of olopatadine hydrochloride on substance P concentrations in nasal secretions and nasal symptoms. World J Exp Med 2026; 16(1): 116584 [DOI: 10.5493/wjem.v16.i1.116584]
Fumihiko Katagiri, Saori Hatoyama-Tanaka, Risa Takayanagi, Yasuhiko Yamada, Department of Clinical Evaluation of Drug Efficacy, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
Tetsuo Watanabe, Masashi Suzuki, Department of Otolaryngology, Head and Neck Surgery, Oita University Faculty of Medicine, Oita 879-5593, Japan
Author contributions: Katagiri F and Watanabe T designed the research study; Katagiri F, Hatoyama-Tanaka S, Takayanagi R, Suzuki M and Watanabe T performed the research; all authors analyzed the data and wrote the manuscript; all authors have read and approve the final manuscript.
Institutional review board statement: This study was reviewed and approved by the local ethical review board (Ethics Committee of Oita University Hospital, No. B01-012).
Informed consent statement: All the individuals who participated in this study provided their written informed consent prior to study enrollment.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CONSORT 2010 statement: The authors have read the CONSORT 2010 statement, and the manuscript was prepared and revised according to the CONSORT 2010 statement.
Data sharing statement: No additional data are available.
Corresponding author: Fumihiko Katagiri, PhD, Lecturer, Department of Clinical Evaluation of Drug Efficacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan. katagiri@toyaku.ac.jp
Received: November 17, 2025 Revised: January 20, 2026 Accepted: February 24, 2026 Published online: March 20, 2026 Processing time: 121 Days and 0.1 Hours
Abstract
BACKGROUND
Olopatadine hydrochloride (olopatadine), a histamine H1 receptor antagonist, inhibits release of substance P (SP) from peripheral nerve endings. It has antiallergic effects and is widely used in dermatology and otolaryngology. It is known that the SP concentration is significantly higher in the nasal secretions of patients with allergic rhinitis than in those of healthy individuals, suggesting a relationship between SP concentrations in nasal secretions and symptoms.
AIM
To investigate effects of olopatadine on SP concentrations in nasal secretions of patients with cedar pollinosis and their relationship with symptoms.
METHODS
Nasal secretions were collected before and after administration of olopatadine to 12 Japanese patients with cedar pollinosis. SP concentrations in nasal secretions were measured and their relationship with scores for nasal symptoms evaluated.
RESULTS
After administration of olopatadine, sneezing, rhinorrhea and severity of symptoms improved significantly (all P < 0.05) and SP concentrations in nasal discharge were significantly lower than before treatment. Our findings suggest that symptoms improve when SP concentrations in nasal secretions decrease. It has been reported that patients with allergic rhinitis have significantly higher concentrations of SP in nasal secretions than healthy individuals, suggesting the importance of controlling SP concentrations when treating allergies.
CONCLUSION
Olopatadine suppresses release of SP, which is involved in itching and inflammation. Our findings suggest that its administration may prove to be a useful new strategy for treating allergies.
Core Tip: Olopatadine hydrochloride (olopatadine), a histamine H1 receptor antagonist, is used to treat various allergic diseases. It has been reported that the concentration of substance P (SP) in the nasal secretions of patients with pollinosis is higher than that of healthy individuals. Furthermore, it has been reported that olopatadine inhibits release of SP. In this study, we found that olopatadine reduces the concentration of SP in the nasal secretions of patients with pollinosis, suggesting that olopatadine reduces SP concentrations and may therefore contribute to improvement in symptoms.
