Efficacy and safety of repeated postoperative administration of intramuscular diclofenac sodium in the treatment of post-cesarean section pain: a double-blind study

Abstract

Background: Analgesic drugs, either opioids or non-opioids, are required and useful for controlling postoperative pain after cesarean section.

Methods: The analgesic and opioid-sparing effects of repeated intramuscular (i.m.) injections of 75 mg of diclofenac sodium given immediately after the experiencing of pain following cesarean section under general anesthesia were studied and compared with placebo in a double-blind trial. One hundred twenty patients 18-40 years of age undergoing elective lower segment cesarean section were treated with either 75 mg diclofenac sodium i.m. (60 patients) or identical placebo (60 patients), once patients awakened from anesthesia and experienced wound pain. Their initial responses to either treatment during the first hour after administration of medications were studied. The analgesic, sedative, and opioid-sparing effects of the medications were also studied during the next 48 h. Side effects including uterine relaxation and bleeding were compared between patients administered placebo and diclofenac.

Results: Results showed that 55/60 patients showed significant pain relief within the first 1 h after administration of diclofenac sodium and their mean pain score decreased from 7.09 +/- 1.06 to 0.85 +/- 0.8 (p <0.05). Within the same period, 10/60 patients responded to placebo injections and mean pain score decreased from 6.6 +/- 0.96 to 0.8 +/- 0.78 (p <0.05). During the first postoperative 48 h, 45 patients showed complete pain relief with use of diclofenac alone while 15 patients required 2,800 mg of pethidine in addition to diclofenac treatment. All patients using placebo required pethidine injection; the total amount of pethidine used was 22,700 mg per 48 h. Verbal scores for sedation were lower in patients treated with diclofenac than in patients treated with placebo at 6 and 12 h postoperatively (p <0.05). There were no significant differences in the proportions of patients who required oxytocin infusion due to uterine relaxation in the diclofenac-treated and the placebo-treated groups (7/60 vs. 12/60, p >0.05).

Conclusions: It might be concluded that repeated i.m. injections of 75 mg diclofenac sodium (maximum two injections per day) could relieve postoperative pain after cesarean section and significantly reduce opioid analgesic requirements without significant effects on uterine relaxation or bleeding during the first postoperative 48 h.