Randomised control trial of oral morphine and intramuscular pethidine for post-caesarean section analgesia in South-Western Nigeria

Abstract

Background: The search for the ideal analgesia following caesarean section remains elusive but opioids provide good postoperative analgesia. Intramuscular opioid induces pain at the site of injection and its repeated administration proved to be more demanding for caregivers. Oral opioids especially morphine have become increasingly accessible in our environment and may be more effective than the conventional parenteral opioids for postcaesarean analgesia. Aim: To compare the efficacy of multiple doses of 10 mg oral morphine with that of 50 mg intramuscular pethidine in treatment of postcaesarean pain among parturients in Abeokuta, Nigeria. Patients, Materials and Methods: The study was a randomised controlled trial among parturients who had elective caesarean section in Abeokuta between November 2019 and August 2020. A total of 136 consenting and eligible pregnant women were randomised into two groups. Group A received multiple doses of 10 mg oral morphine while Group B had multiple doses of 50 mg intramuscular pethidine. The summed pain intensity difference (SPID) of the two groups was calculated and compared using the Chi-square and P < 0.05 was statistically significant. Results: The mean ± standard deviation (SD) of SPID at rest for morphine group and pethidine group was 6.00 ± 76.25 and 8.51 ± 77.60, respectively (t = −0.439 P = 0.662); the mean ± SD of SPID on movement for morphine and pethidine group was 29.13 ± 75.25 and 25.52 ± 28.47 (t = 0.139, P = 0.890). The median maternal satisfaction reported was similar in both groups (χ2 = 2.773, P = 0.4963) and somnolence was experienced in 3.1% of parturients in morphine group. Conclusion: The efficacy and maternal satisfaction of oral morphine in the control of postcaesarean section pain was similar to that of intramuscular pethidine. Hence, oral morphine is an acceptable alternative to intramuscular pethidine in management of pain following Caesarean section.