Effect of intravenous dexamethasone combined with dexmedetomidine and magnesium on analgesic effect of ultrasound-guided transverse abdominis plane block: a randomized controlled trial

Despite the minimally invasive nature of laparoscopic surgery, postoperative pain remains a highly prevalent clinical issue. Whether dexamethasone combined with different local anesthetic adjuvants can optimize the analgesic efficacy of ultrasound-guided transversus abdominis plane block (TAPB) remains inconclusive. This study aimed to investigate the analgesic effect of dexamethasone combined with different adjuvants for TAPB in laparoscopic surgery. This randomized controlled trial enrolled 200 eligible patients undergoing laparoscopic surgery with TAPB, randomly assigned to 4 groups ( n = 50 each): dexamethasone alone (Group D), dexamethasone plus dexmedetomidine (Group DD), dexamethasone plus magnesium sulfate (Group DE), and dexamethasone plus both adjuvants (Group DM). The primary outcome was time to first patient-controlled intravenous analgesia (PCIA) request within 72 h postoperatively. Time to first PCIA request was significantly prolonged in Group DD (724.0,515.0) and Group DM (843.0,587.5) versus Group D (220.0,155.0), with Bonferroni p value < 0.01. With significantly lower 72-h PCIA use incidence ( P < 0.05). No statistically significant differences were observed between Group DE and Group D. Dexamethasone combined with dexmedetomidine for TAPB provides superior postoperative analgesia and reduces opioid consumption in laparoscopic surgery, while 200 mg magnesium sulfate offers no additional analgesic benefit. Trial registration The study has been registered with the China Clinical Trial Registration Center (ID: ChiCTR2300071199), on May 08, 2023.