Efficacy of oxycodone in managing visceral pain among women undergoing repeat cesarean section: a randomized...

The global cesarean section (CS) rate is on the rise, with ratio of repeat CS becoming more common in China following the two-child policy. Postoperative visceral pain, particularly intense in repeat CS parturients and exacerbated by oxytocin, remains inadequately managed. Oxycodone, acting via κ-opioid receptors, has shown promise in relieving visceral pain, but its efficacy in repeat CS populations is unclear, which was explored in this study.

This randomized controlled trial enrolled 100 parturients undergoing elective repeat CS, randomized to patient-controlled intravenous analgesia (PCIA) with oxycodone (50 mg/100 ml) or sufentanil (100 μg/100 ml). Primary outcomes were maximum visceral pain Numerical Rating Scale (NRS) scores during 0-24 h postoperatively. Secondary outcomes included visceral pain NRS during oxytocin administration on postoperative days 1-2, postoperative inflammatory markers (neutrophil-to-lymphocyte ratio, NLR), time to autonomic activity and PCIA presses. This trial was registered with the Chinese Clinical Trial Registry (ChiCTR2400087624; July 31 2024).

Significantly lower maximum visceral pain NRS scores in the oxycodone group during 24h after surgery compared to sufentanil group (2.2 ± 0.6 vs. 3.4 ± 0.7, P < 0.001), and also at all time points during oxytocin infusion (P < 0.001). The oxycodone group also had shorter time to autonomic activity (23.7 ± 5.1 vs. 26.3 ± 3.4 h, P = 0.004), lower postoperative NLR (7.2 ± 2.1 vs. 9.1 ± 3.7, P = 0.003), and fewer PCIA presses (P = 0.002). Multivariate linear regression confirmed oxycodone as an independent predictor of reduced maximum postoperative pain (adjusted β = -1.13, 95%CI:-1.41 to-0.85, P < 0.001).

In conclusion, oxycodone effectively alleviates postoperative visceral pain and mitigates inflammatory responses in repeat CS parturients, making it a preferred choice for postoperative analgesia in this population.