Open-Label Exploration of an Intravenous Nalbuphine and Naloxone Mixture as an Analgesic Agent Following Gynecologic Surgery

Objective. The purpose of this series was to explore a 12.5:1 fixed-dose ratio of an intravenous nalbuphine and naloxone mixture (NNM) for use in patients following gynecologic surgery. Design and Patients. Open-label, nonrandomized case series. The first series was a dose-ranging investigation for 12 patients following elective total abdominal hysterectomy or myomectomy. In this series, fentanyl was used for intraoperative analgesia, and patients were assigned to a lower NNM (2.5 mg/0.2 mg) or to a higher NNM (5 mg/0.4 mg) dose group. The second series evaluated the fixed dose of 5 mg nalbuphine/0.4 mg naloxone for four patients undergoing ambulatory gynecologic procedures. In the second series, no opioid agents were administered intraoperatively to eliminate the possibility of mu-opioid reversal by naloxone postoperatively. Outcome Measures. Pain control was assessed using a Verbal Pain Scale (0–10). Vital signs, side effects, and adverse events were recorded to determine drug safety. Results. In the first series, there were no adverse events; however, each patient required rescue medication (either morphine or fentanyl). In the second series, two of the four patients reported a reduction in pain following drug administration and did not require any further analgesic agents in the 3-hour postoperative period. One patient had an asymptomatic lowering of heart rate after receiving the drug. Conclusion. Additional research of the unique combination therapy of nalbuphine and naloxone is warranted to further determine its potential clinical efficacy and safety.