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Olanzapine-based vs neurokinin-1 receptor antagonist antiemetic regimens in highly emetogenic chemotherapy: Systematic review and meta-analysis of efficacy and safety
Advaitha Mv, Nikhilesh Anand, Biacin Babu, Ayoola Awosika, Uttam Udayan, Jacqueline Mendoza, Alissa Lopez, Brahmaiahchari Rangachari, Sabyasachi Maity, Bharathi S Gadad
Advaitha Mv, Department of Pharmacology, Nitte (Deemed to be University), KS Hegde Medical Academy, Mangalore 575018, Karnātaka, India
Nikhilesh Anand, Uttam Udayan, Jacqueline Mendoza, Alissa Lopez, Bharathi S Gadad, Department of Medical Education, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78542, United States
Biacin Babu, Department of Pharmacology, Vardhman Mahavir Medical College & Safdarjung Hospital, New Delhi 110029, Delhi, India
Ayoola Awosika, Department of Family and Community Medicine, University of Illinois College of Medicine Peoria, Bloomington, IL 61601, United States
Brahmaiahchari Rangachari, Department of Pathology, Kentucky College of Osteopathic Medicine, Pikeville, KY 41501, United States
Sabyasachi Maity, Department of Cellular and Integrative Physiology, Long School of Medicine, UT Health San Antonio, San Antonio, TX 78015, United States
Author contributions: Mv A, Anand N, Babu B, Awosika A, and Udayan U contributed to conceptualization and overall coordination; Mv A, Anand N, Babu B, Awosika A, Udayan U, Mendoza J, Rangachari B, Maity S, and Gadad BS contributed to literature search, evidence acquisition and data extraction, interpretation and synthesis of evidence, and writing - original draft preparation; Mv A, Anand N, Babu B, Awosika A, Mendoza J, Lopez A, Gadad BS contributed to writing - review and editing; Mv A and Awosika A contributed to supervision and senior oversight. All authors agreed and are accountable for all aspects of the work in ensuring accuracy/integrity of all sections of the manuscript, and everyone have given final approval of the manuscript version to be published.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Corresponding author: Ayoola Awosika, MD, Department of Family and Community Medicine, University of Illinois College of Medicine Peoria, 1 Illini Drive, Bloomington, IL 61601, United States.
ayoolaawosika@yahoo.com
Received: January 20, 2026
Revised: February 3, 2026
Accepted: March 6, 2026
Published online: April 26, 2026
Processing time: 85 Days and 22.2 Hours
BACKGROUND
Chemotherapy-induced nausea and vomiting is common in patients who receive highly emetogenic chemotherapy (HEC). Olanzapine acts on multiple neurotransmitters and effectively reduces delayed-phase nausea.
AIM
To compare the safety and efficacy of olanzapine-based vs neurokinin-1 receptor antagonist-based antiemetic regimens in adults receiving HEC.
METHODS
This review followed Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 guidelines and searched various databases like PubMed, Scopus, etc., between 2020-2025. 14 studies were included in the systematic review with 11 meeting the criteria for meta-analysis. Primary outcomes were complete response (no vomiting, no rescue medication) and nausea control during acute (0-24 hours), delayed (25-120 hours), and overall (0-120 hours) phases. Data were pooled using random-effects models. Risk of bias was assessed with Cochrane risks of bias 2.0 and risk of bias in nonrandomized studies of interventions version I tools.
RESULTS
Olanzapine-based regimens showed higher nausea control, with no-nausea rates of 89% vs 76% (P < 0.001) and 96% vs 87% (P = 0.005). Acute complete response ranged from 66% to 100%, delayed complete response from 55% to 94%, and overall complete response from 63% to 91%. The pooled complete response odds ratio was 48.68 (95% confidence interval: 8.33-284.64; P < 0.0001). Sedation occurred in 10%-53% of patients and showed dose dependence, with lower rates at 5 mg. Most studies showed low risk of bias and high methodological quality, supporting reliability of pooled estimates despite high heterogeneity (I2 > 95%).
CONCLUSION
Olanzapine-based regimens are at least as effective as neurokinin-1 antagonist therapy for chemotherapy-induced nausea and vomiting in HEC, particularly for delayed nausea. Low-dose (5 mg) olanzapine provides effective, well-tolerated, oral, and cost-efficient prophylaxis, supporting its use as a first-line antiemetic.
Core Tip: Chemotherapy-induced nausea and vomiting commonly occur in patients receiving highly emetogenic chemotherapy, with rates over 90% without prophylaxis. Effective prevention preserves quality of life, supports treatment adherence, and reduces healthcare use. This study demonstrated that olanzapine-based regimens effectively prevent chemotherapy-induced nausea and vomiting in patients receiving highly emetogenic chemotherapy, with pronounced control of delayed-phase nausea. Low dose provides predictable efficacy, manageable sedation, oral convenience, and cost-effectiveness. Clinically, olanzapine should be included in first-line antiemetic protocols to improve patient comfort, reduce the need for rescue medication, and support adherence to treatment.
