Comparison of two different doses of preemptive gabapentin on postoperative pain relief and morphine requirement after mastectomy: A randomized study

Abstract

Background and Aims: Gabapentin (GBP) has been found to decrease the pain scores and analgesic requirements following total abdominal hysterectomy, spinal surgery, and ear, nose, and throat surgery. It has been suggested that central neuronal sensitization may play an important role in postoperative pain. This study compares the effect of two different doses of preemptive GBP on morphine requirement and postoperative pain relief in patients undergoing mastectomy. Methods: This randomized comparative trial included 70 patients scheduled for unilateral mastectomy. They were divided into two groups. Group 1 received 800 mg oral GBP and Group 2 received 1200 mg oral GBP 2 h before surgery. After surgery, we recorded the pain score at different time points using the Visual Analog Scale (VAS) at rest. Patients were also asked about possible side effects of the premedication drug. Patients received morphine 0.1 mg/kg intravenous on demand. The time of first rescue analgesia was recorded along with the total rescue analgesic requirement in the first 24 h. Results: In our study, the mean VAS score, postoperatively at 2, 4, 12, 24 h in Group 2, was less than Group 1 but the difference was not statistically significant (P = 0.9, 0.1, 0.8, 0.4, respectively) Patients of Group 1 demanded rescue analgesia earlier (5.8 ± 3.4 h) than Group 2 (9.6 ± 5.9 h). The total 24 h morphine consumption in Group 1 (10.97 ± 4.01 mg) was higher than Group 2 (6.71 ± 5.02 mg). No significant side effects were observed during the perioperative period. Conclusion: We conclude that GBP in higher doses, when used preemptively, provides a greater degree of analgesia with opioid-sparing effect.

Keywords

• analgesia
• gabapentin
• preemptive
• radical mastectomy