Opioid sparing effect of post induction intramuscular midazolam following myomectomy

Abimbola, J, Adenekan A, Owojuyigbe A, Orji E, Owojuyigbe T, Aaron O.  2020.  Opioid sparing effect of post induction intramuscular midazolam following myomectomy, 2020/10/01. 27:187-195.


Background: Adequate post-operative pain control is essential for smooth recovery after surgery. This study assessed the opioid-sparing effect of immediate post-induction intramuscular midazolam in patients who underwent myomectomy under general anesthesia.Methods: This is a randomized double-blinded controlled study of sixty ASA I and II female patients allocated into three groups. Group A received intramuscular midazolam 0.1mg/kg, group B received intramuscular diclofenac 75mg while group C had a placebo following induction of anesthesia. All patients had morphine 0.1mg/kg for intraoperative analgesia before skin incision. Pain scores were compared at recovery, then at 1st, 2nd, 4th and 8th post-operative hours. In addition, the total opioid consumption over the first 24 hours postoperatively was compared between the three groups.
Results: The pain scores at the end of surgery, 1st and 2nd hours were comparable in the 3 groups; however there was statistically significant difference at the 4th hour postoperatively (p = 0.0001), with lowest pain scores in the midazolam and diclofenac groups (3.70 ± 0.66 and 3.80 ± 1.01 respectively) compared to the placebo group (4.75 ± 0.79). The total additional opioid (pentazocine) consumption in first 24 hour after surgery was significantly reduced in the midazolam group (105.00 ± 15.39 mg) compared to diclofenac and placebo groups (112.50 ± 13.33 mg, and 121.50 ± 18.14 mg respectively, p = 0.007).
Conclusion: Post induction intramuscular Midazolam at 0.1mg/kg appears to have a better opioid sparing effect compared to intramuscular diclofenac 75mg in the early postoperative period
following myomectomy done under general anesthesia.