Dexamethasone, a synthetic steroid hormone, has been extensively studied for its role as an adjuvant in peripheral nerve blocks, an anesthesia technique used to manage perioperative pain. Peripheral nerve blocks involve the injection of local anesthetics near specific nerves to inhibit pain signals. While effective, the duration of analgesia provided by these blocks is often limited. Dexamethasone is increasingly used to prolong the analgesic effects of these blocks, thereby enhancing postoperative pain management and reducing the need for additional analgesics.
Research has shown that using the steroid hormone dexamethasone as an adjuvant to local anesthetics in peripheral nerve blocks significantly extends the duration of analgesia. A randomized controlled trial conducted by Choi et al. demonstrated that patients receiving dexamethasone experienced prolonged sensory and motor blockade compared to those receiving local anesthetic alone. This effect is attributed to the anti-inflammatory properties of steroid drugs, which reduce perineural inflammation and inhibit ectopic neural discharge, thereby enhancing the efficacy of the block (1). The mechanism by which dexamethasone prolongs the analgesic effect of nerve blocks involves several pathways. One proposed mechanism is the suppression of the nociceptive C-fiber activity. Dexamethasone induces vasoconstriction, which limits the systemic absorption of local anesthetics, thereby maintaining higher local concentrations of the anesthetic near the nerve. Additionally, dexamethasone exerts a direct effect on the nerve by inhibiting the release of inflammatory mediators and reducing neural edema, contributing to prolonged analgesia (2).
Clinical studies have provided substantial evidence supporting the efficacy of dexamethasone as a steroid adjuvant in various types of peripheral nerve blocks, including brachial plexus blocks and femoral nerve blocks. In a meta-analysis by Huynh et al., dexamethasone was associated with a significant increase in the duration of analgesia and a decrease in opioid consumption postoperatively. Patients receiving dexamethasone as an adjuvant reported lower pain scores and required fewer rescue analgesics, highlighting its potential to improve patient outcomes and satisfaction (3). Despite its benefits, the use of dexamethasone as an adjuvant in peripheral nerve blocks is not without potential risks. Concerns have been raised regarding the neurotoxicity of dexamethasone, although current evidence suggests that when used in clinically appropriate doses, it is safe. Studies have not demonstrated significant neurotoxic effects when dexamethasone is used in peripheral nerve blocks, but long-term data are still needed to fully establish its safety profile (4).
The optimal dose of dexamethasone for prolonging analgesia in peripheral nerve blocks is still a subject of investigation. Doses ranging from 4 mg to 10 mg have been studied, with most studies indicating that 4 mg is sufficient to achieve significant analgesic prolongation without increasing the risk of adverse effects. Higher doses do not appear to confer additional benefits and may increase the risk of side effects, such as hyperglycemia and immunosuppression (5). The administration route of dexamethasone also influences its efficacy. Perineural administration, where dexamethasone is injected directly around the nerve, appears to be more effective than intravenous administration for prolonging block duration. However, intravenous dexamethasone still provides some benefits in extending analgesia and reducing postoperative pain, suggesting that it can be a useful alternative when perineural administration is not feasible (1).
In conclusion, dexamethasone is a useful steroid adjuvant in peripheral nerve blocks, significantly enhancing the duration of analgesia and improving postoperative pain management. Its benefits include prolonged sensory and motor blockade, reduced opioid consumption, and improved patient satisfaction. While concerns about its long-term safety and optimal dosing remain, current evidence supports its efficacy and safety in clinical practice. Further research is warranted to establish standardized dosing protocols and to explore the long-term effects of dexamethasone in peripheral nerve blocks.
References
- Choi S, Rodseth R, McCartney CJ. Effects of dexamethasone as a local anaesthetic adjuvant for brachial plexus block: a systematic review and meta-analysis of randomized trials. Br J Anaesth. 2014;112(3):427-439. doi:10.1093/bja/aet417
- Cummings KC 3rd, Napierkowski DE, Parra-Sanchez I, et al. Effect of dexamethasone on the duration of interscalene nerve blocks with ropivacaine or bupivacaine. Br J Anaesth. 2011;107(3):446-453. doi:10.1093/bja/aer159
- Huynh TM, Marret E, Bonnet F. Combination of dexamethasone and local anaesthetic solution in peripheral nerve blocks: A meta-analysis of randomised controlled trials. Eur J Anaesthesiol. 2015;32(11):751-758. doi:10.1097/EJA.0000000000000248
- Parrington SJ, O’Donnell D, Chan VW, et al. Dexamethasone added to mepivacaine prolongs the duration of analgesia after supraclavicular brachial plexus blockade. Reg Anesth Pain Med. 2010;35(5):422-426. doi:10.1097/AAP.0b013e3181e85eb9
- Kirkham KR, Jacot-Guillarmod A, Albrecht E. Optimal Dose of Perineural Dexamethasone to Prolong Analgesia After Brachial Plexus Blockade: A Systematic Review and Meta-analysis. Anesth Analg. 2018;126(1):270-279. doi:10.1213/ANE.0000000000002488
Recent Comments