Abstract
BACKGROUND: Moderate to severe postoperative pain is frequent in patients undergoing surgery and is associated with increased morbidity and prolonged hospitalisation. Therefore, sufficient pain management should be prioritised. Clonidine, an alpha-2 agonist with analgesic properties, may represent a relevant option in postoperative pain management. While clonidine is commonly used in a clinical setting, the quality of evidence supporting its perioperative use is limited by small sample sizes, heterogeneous study designs, and variations in administration routes. This systematic review aims to evaluate the benefits and harms of perioperative clonidine in postoperative pain management. METHODS: We will conduct a systematic review of randomised clinical trials assessing the effects of perioperative clonidine on postoperative pain intensity, adverse effects, and postoperative opioid consumption. This review will include trials using perioperative systemic (oral, intravenous, transdermal, or intramuscular) clonidine and trials using placebo or no intervention as the control intervention. We will systematically search Medline, Embase, and the Cochrane Central Register of controlled trials for relevant literature. The recommendations by the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) are followed for this protocol, and the PRISMA guidelines will be followed in the actual review. The certainty of evidence will be assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. OUTCOMES: The primary outcomes are postoperative pain intensity and serious adverse events. Secondary outcomes include postoperative opioid consumption, quality of life, and non-serious adverse events. DISCUSSION: Although clonidine is used in a clinical setting to manage postoperative pain, the benefits and harms of this intervention remain unclear. CONCLUSION: This systematic review will provide valuable information on the efficacy and safety of perioperative clonidine in postoperative pain management.