Comparison of the Efficacy of Intravenous, Subcutaneous, and Suppository Morphine in Reducing Post Hysterectomy Pain

Background and aims: Postoperative pain has always been considered by surgeons because of its various complications. The aim of this study was to compare the effect of intravenous, subcutaneous and suppository morphine in reducing post-hysterectomy pain. Materials and Methods: In this clinical trial, 90 patients undergoing hysterectomy were randomized into three groups of 30 each using simple randomization, namely, intravenous, subcutaneous, and suppository morphine (10 mg). Before intervention and 4, 8, 12, and 16 hours after intervention, pain intensity was measured using visual analogue scale (VAS). Relative frequency of nausea, vomiting, itching, bradypnea, and apnea in all groups was recorded. Data were analyzed by SPSS version16.0. Results: Mean pain severity at 0 hour postoperatively (P=0.004), 4 hours postoperatively (P=0.009), 8 hours postoperatively (P=0.009), and 12 hours postoperatively (P=0.001) was significantly higher in the suppository morphine group than in the other two groups. There was no significant difference in pain severity at 16 hours postoperatively among the three groups (P=0.446). According to the results of repeated measures ANOVA, changes in pain severity at the five intervals were statistically significant in all three groups (subcutaneous, intravenous, and suppository morphine groups) (P<0.001). There was also a statistically significant difference in pain severity at the studied intervals among the three groups (P<0.001). The frequency of nausea (P=0.05) and vomiting (P=0.84) was higher in the suppository group than in the other two groups, although the difference was not statistically significant (P=0.05). Conclusion: The results of this study indicated better efficacy of subcutaneous and intravenous morphine in reducing post-hysterectomy pain compared with suppository morphine.