BACKGROUND: Orthopaedic procedures often cause intense postoperative pain, posing challenges for effective management. Brachial plexus blocks offer relief but optimising analgesia with minimal local anaesthetic is still challenging. Perineural dexamethasone, with anti-inflammatory effects, shows promise in lower doses but lacks sufficient research. OBJECTIVE: The study aims to assess low-dose perineural dexamethasone in ultrasonography-guided brachial plexus blocks for extending analgesia and reducing opioid use in upper limb surgeries. METHODS: Double-blinded trial on 90 American Society of Anaesthesiologists class I or II patients undergoing upper limb procedures. The patients were divided into two groups and received bupivacaine with either 4 mg dexamethasone (Group D) or saline (Group C). Analgesia duration was evaluated via the Numerical Pain Rating Scale and adverse events were recorded. FINDINGS: The dexamethasone group showed significantly longer analgesia (1253.33 ± 41.00 vs. 714.67 ± 32.80 min, p <
0.001) and lower Numerical Pain Rating Scale scores at 4, 8, 12, and 24 h postoperatively. Minimal adverse events were observed in both groups, with mild nausea being the only event reported. CONCLUSIONS: In upper limb procedures, low-dose perineural dexamethasone improves postoperative pain management with few side effects. It presents a viable adjunct for enhancing pain management techniques.