Comparison of epidural oxycodone and epidural morphine for post-caesarean section analgesia: A randomised controlled trial

Abstract

Background and Aims:Epidural morphine after caesarean section may cause moderate to severe pruritus in women. Epidural oxycodone has been shown in non-obstetric trials to reduce pruritus when compared to morphine. We hypothesised that epidural oxycodone may reduce pruritus after caesarean section.Methods:A randomised controlled trial was conducted in pregnant women at term who underwent caesarean section with combined spinal-epidural technique initiated with intrathecal fentanyl 15 μg. Women received either epidural morphine 3 mg or epidural oxycodone 3 mg via the epidural catheter after delivery. The primary outcome was the incidence of pruritus at 24 h after caesarean section. The secondary outcomes were the pruritus scores, treatment for post-operative nausea and vomiting (PONV), pain scores and maternal satisfaction.Results:One hundred women were randomised (group oxycodone O = 50, morphine M = 50). There was no difference between Group O and M in the incidence of pruritus (n [%] 28 [56%] vs. 31 [62%], P = 0.68) and the worst pruritus scores (mean [standard deviation] 2.6 (2.8) vs. 3.3 [3.1], P = 0.23), respectively. Both groups had similar pain scores at rest (2.7 [2.3] vs. 2.0 [2.7], P = 0.16) and sitting up (5.0 [2.3] vs. 4.6 [2.4], P = 0.38) at 24 h. Pruritus scores were lower at 4–8, 8–12 and 12–24 h with oxycodone, but pain scores were higher. Both groups had a similar need for treatment of PONV and maternal satisfaction with analgesia.Conclusion:There was no difference in the incidence of pruritus at 24 h between epidural oxycodone and morphine. However, pruritus scores were lower with oxycodone between 4 and 24 h after surgery with higher pain scores in the same period.

The analgesic efficacy and pharmacokinetics of epidural oxycodone after gynaecological laparotomy: a randomized, double‐blind, double‐dummy comparison with intravenous administration

“…Epidural administration of oxycodone has been evaluated in few previous clinical trials . In the study by Bäcklund et al .…”

“…Intrathecal opioids cause a higher incidence of pruritus compared with other administration routes, and this should be taken in account when using epidural oxycodone. The incidence of pruritus seems to be similar after epidural oxycodone and epidural morphine .…”

“…Epidural administration of oxycodone has been evaluated in few previous clinical trials [4,[14][15][16][17]. In the study by Bäcklund et al [14], epidural oxycodone had no benefit over i.v.…”

Analgesic efficacy and pharmacokinetics of epidural oxycodone in pain management after gynaecological laparoscopy—A randomised, double blind, active control, double‐dummy clinical comparison with intravenous administration

“…Six previous studies have evaluated the epidural administration of oxycodone, of which 3 have compared oxycodone with morphine . These data indicate that when administrated epidurally, at least 2‐times higher dose of oxycodone is needed to provide similar analgesia compared to morphine . This is not expected based on the physiochemical properties of these 2 compounds as liposolubility and protein‐binding of oxycodone are similar to morphine .…”

Updated Clinical Pharmacokinetics and Pharmacodynamics of Oxycodone

“…In post caesarean section pain, 3 mg of epidural oxycodone or morphine provided similar pain relief at rest, but dynamic pain control was inferior with oxycodone. This indicates that in epidural administration, the potency ratio between oxycodone and morphine is less than 1:1 [130].…”