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.