Preoperative gabapentin alone or in combination with dexamethasone on postoperative pain relief after abdominal hysterectomies. A randomized controlled trial

Objectives
To investigate the role of combining preoperative gabapentin with dexamethasone in the management of post-operative pain following abdominal hysterectomy.
Methods
This prospective randomized double blinded study included 60 females scheduled for abdominal hysterectomy under general anesthesia. They were randomized into three equal groups [20 patients each]; group C [Control]: received oral placebo and intravenous 2 cc normal saline 0.9%, group G [Gabapentin]: received 800 mg gabapentin orally and intravenous 2 cc normal saline 0.9% and group GD [Gabapentin/Dexamethasone]: received 800 mg gabapentin orally and intravenous 8 mg/2 cc dexamethasone. Intraoperative fentanyl requirement, postoperative pain, sedation and nausea and vomiting were assessed at 2, 6, 12 and 24 h postoperative. Time of the first request for analgesia and total postoperative meperidine dose over 24 h were calculated.
Results
Intraoperative fentanyl requirement, time of the first analgesic request, total 24 h meperidine consumption and VAS score at 2 and 6 h postoperatively showed highly statistically significant difference between group (GD) [added dexamethasone to gabapentin] and gabapentin (G) alone or control (C), meanwhile there was statistically significant difference between (G) and (C) groups. VAS score was statistically significant lower among the three studied groups when assessed at 12 h postoperatively. There were no statistically significant differences among the three groups as regards the postoperative sedation scale. PONV was highly statistically significant less observed in groups (GD) and (G) at 2 h and statistically significant less observed at 6 h postoperatively when compared to the control group (C).
Conclusion
Gabapentin alone reduced the intraoperative and postoperative opioid requirement as well as postoperative pain and PONV which was significant in comparison with the placebo effect in the control. Obviously these effects were more prominent and highly significant when dexamethasone was added to gabapentin.