Efficacy and safety of preoperative intranasal dexmedetomidine in adults: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Airway manipulation during General Anesthesia (GA) can produce sympathetic activation and hemodynamic instability. Intravenous (IV) dexmedetomidine attenuates these responses but may cause bradycardia or hypotension. Intranasal (IN) administration is a noninvasive alternative with uncertain evidence in adults. We evaluated preoperative IN dexmedetomidine in adult patients undergoing GA. METHODS: We performed a PROSPERO-registered (CRD420251250492) systematic review and meta-analysis of randomized trials. MEDLINE, Embase, CENTRAL, and CDSR were searched from inception to November 26, 2025. IN dexmedetomidine versus control and IN vs. IV dexmedetomidine were assessed separately. Random-effects models pooled continuous outcomes as MDs/SMDs and adverse events as RRs. Risk of bias was assessed using RoB2 and certainty of evidence using GRADE. RESULTS: Across 25 trials including 1,968 patients, IN dexmedetomidine was associated with deeper sedation (SMD = 0.76; 95% CI: 0.18-1.34) and reduced heart rate and mean arterial pressure at induction, intubation, and during the early intraoperative period compared with control (MD range: -12.7 to -13.4 bpm and -7.8 to -10.7 mmHg, respectively). Rates of bradycardia and hypotension were similar between IN dexmedetomidine and control groups. Compared with IV dexmedetomidine, IN administration resulted in lighter sedation (SMD = -0.54; 95% CI: -1.08 to -0.01), with similar hemodynamic effects, while bradycardia and hypotension occurred less frequently. CONCLUSION: Preoperative IN dexmedetomidine may improve sedation and blunt peri-induction hemodynamic responses compared with controls, with broadly similar hemodynamic effects and fewer observed cardiovascular adverse events versus IV administration. However, certainty was low or very low for several efficacy outcomes, and larger well-designed trials are needed.