Efficacy and safety of adjuvants in peripheral nerve blocks: a systematic review of randomized clinical trials (2019–2025)
Ian Pagnussat, Beatriz Nascimento Vieira, Inácia Goncalves Simões Lordello, Fabrício Tavares Mendonça
Abstract
Background: Peripheral nerve blocks are fundamental strategies for perioperative pain management. The present study aimed to review the literature published in the past five years regarding the use and clinical implications of adjuvants in these blocks. Methods: This systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and was prospectively registered in the PROSPERO database (CRD420251115701). The literature search was conducted using PubMed, Web of Science, and Embase databases, covering the period from January 2019 to June 2025. Randomized controlled trials (RCTs) evaluating the use of adjuvants in peripheral nerve blocks were included. The primary outcome analyzed was analgesic efficacy, and secondary outcomes included block duration, analgesic consumption, adverse effects, and procedure-related complications. Results: A total of 23 studies were included in the analysis. The results demonstrated that dexmedetomidine was the most investigated adjuvant (52.2%), followed by dexamethasone (30.4%) and its combination (17.4%), reflecting growing interest in these agents. Approximately 75–80% of the studies demonstrated significant clinical benefits, including reduced pain scores, prolongation of analgesia (an average of 2–6 additional hours), and lower opioid consumption (reductions of 20–40%). Regarding safety, most studies reported a low incidence of adverse events; when present, mild sedation, bradycardia or hypotension were generally transient and self-limited. Conclusion: This review identified that the addition of adjuvants to local anesthetics may represent a promising strategy to prolong analgesia, reduce postoperative pain scores, decrease opioid consumption and improve overall patient experience, especially in procedures of moderate and high complexity. However, the strength of evidence varies across studies, and further high-quality trials are warranted to establish their efficacy and safety profiles better.
Keywords
References
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Submitted date:
02/17/2026
Accepted date:
08/21/2026
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