Dose ranging effects of pregabalin on pain in patients undergoing laparoscopic hysterectomy: A randomized, double blinded, placebo controlled, clinical trial

Objective: The study aimed to investigate the preemptive analgesia efficacy of different concentrations (75, 150 and 300mg) of preemptive pregabalin for the postoperative pain management after laparoscopic hysterectomy.

Design: Prospective, randomized, placebo-controlled, double-blind study.

Setting: The Gynecology and Obstetrics Center of Arash Hospital, Tehran, Iran, from October 2013 to November 2014.

Patients: A total of 96 women with American Association of Anesthesiologist (ASA) physical status I and II underwent elective laparoscopic hysterectomy surgery. Patients were then randomly assigned to four groups, of which groups 1-3 (treatment groups; n=20) received orally pregabalin concentrations of 75mg, 150mg, and 300mg, respectively, for a night before surgery, 30min before surgery and 6h after surgery, whereas group 4 (control group; n=22) received a matching dosage of placebo at the same scheme.

Measurements: Visual Analog Scale (VAS) scores for postoperative pain at rest and on movement at first 24h after surgery were evaluated as primary outcome. Drug-related side effects were also evaluated as a secondary outcome. Somnolence was evaluated using Ramsay Sedation Scale, while nausea and vomiting were assessed using numeric scores. The data were analyzed using SPSS.

Main results: Preemptive pregabalin in different concentrations provided better pain relief as compared with placebo. Post-hoc test indicated that there was a significant difference among four groups, indicating where the concentration was increased, the pain score decreased as an independent variable of time. The highest concentration of pregabalin (300mg) revealed higher sedation scores as compared with other groups.

Conclusion: Our data demonstrated preemptive administration of 75, 150, and 300mg pregabalin play an important role in reducing postoperative pain after laparoscopic hysterectomy. Comparison of different concentrations and side effects indicates oral administration of 150mg pregabalin is an effective and safe method for postoperative pain management after laparoscopic hysterectomy.