Comparison of the efficacy of pentazocine and tramadol for reducing emergence agitation in children after general anesthesia: a retrospective cohort study.

backgroundEmergence agitation (EA) is a common postoperative complication in pediatric anesthesia that can lead to serious safety events and increased healthcare burden. Both pentazocine and tramadol are frequently used for postoperative analgesia in children, but their comparative effectiveness in preventing EA remains unknown. This study aimed to compare the efficacy of a single intravenous dose of tramadol versus pentazocine for reducing EA in children undergoing tonsillectomy and adenoidectomy.

methodsThis single-center retrospective cohort study included 240 children aged 2-12 years who underwent elective tonsillectomy and adenoidectomy under general anesthesia with remimazolam induction. Patients received either pentazocine 0.4 mg/kg or tramadol 1 mg/kg intravenously immediately after surgery. The primary outcome was the incidence of EA, defined as a Pediatric Anesthesia Emergence Delirium (PAED) scale score ≥ 10 at any time during the post-anesthesia care unit (PACU) stay. Secondary outcomes included PAED score trajectories over time, PACU stay duration, postoperative pain (FLACC scale), and adverse events (nausea/vomiting, respiratory depression). Statistical analyses primarily used multivariable logistic regression; secondary and sensitivity analyses (linear mixed models, generalized estimating equations, spline-based models, and Cox regression) were performed to assess robustness and are detailed in the Supplementary Material.

resultsThe unadjusted incidence of EA was 0.8% (1/120) in the tramadol group and 14.2% (17/120) in the pentazocine group (relative risk 17.00, 95% CI: 2.30-125.73, p < 0.001). Multivariable logistic regression, adjusting for potential confounders, showed that the pentazocine group had higher odds of EA (OR = 12.61, 95% CI: 2.33-234.43, p = 0.017), although the wide confidence intervals reflect the low event rate. Linear mixed models suggested a significant group-by-time interaction (p < 0.001), with higher PAED scores in the pentazocine group at 5 and 10 min but convergence by 20 min. Exploratory time-to-event analyses (Kaplan-Meier and Cox regression) suggested that the pentazocine group had a slower agitation resolution rate compared with the tramadol group (HR = 0.73, 95% CI: 0.56-0.96, p = 0.025), consistent with faster resolution in the tramadol group. However, these results should be interpreted cautiously due to fixed-time assessments. PACU stay was shorter in the tramadol group (median 32 vs. 34 min, p < 0.001). Adverse event rates were low and comparable between groups. Extended analyses (GEE, spline-based models) consistently supported the primary findings (see Supplementary Material).

conclusionIn this retrospective cohort, tramadol was associated with a lower incidence of EA and faster recovery compared with pentazocine, without an observed increase in short-term adverse events. The adjusted odds ratio of 12.61 has an extremely wide 95% CI, reflecting statistical instability; this estimate should not be interpreted as a precise effect size. Due to the very low event rate (one event in the tramadol group) and other limitations (retrospective design, potential residual confounding), these findings should be considered hypothesis-generating and suggestive rather than definitive. Further prospective studies are needed to confirm whether tramadol offers a clinically meaningful advantage over pentazocine in this population.