TITLE: INTRATHECAL FENTANYL WITH NALBUPHINE FOR LABOR ANALGESIA

AUTHORS: Eveline Faure, MD, Bernard Wittels, MD, PhD, Jerome Klafta, MD, Alicia Toledano, ScD, Michelle Freind, DO, Atef Moawad, MD
AFFILIATION: University of Chicago, Chicago, IL.

INTRODUCTION: Intrathecal (IT) opiates are commonly used in combination with epidural analgesia (CSE) to relieve labor pain. The reported side effects of IT opioids are pruritus (67- 100%) nausea, vomiting, and respiratory depression, which are mediated by µ-receptors (1). Nalbuphine, a µ-antagonist, has been successfully administered to counteract these side effects. We tried to determine whether nalbuphine added to IT fentanyl would prolong analgesia and attenuate the side effects.
METHODS: The study was conducted with IRB approval and informed consent from 70 patients. Inclusion criteria were near term gestation, (>36 wk gestational age); singleton fetus in the vertex position; uncomplicated labor as determined by maternal vital signs, contractions, fetal heartbeat tracings; no history of drug use or allergy to the study drugs; and request for epidural analgesia for labor. An 18-g Husted epidural needle was inserted and advanced to the epidural space using the loss of resistance technique. A 24-g, 119-mm Whitacre spinal needle was introduced though the epidural needle into the subarachnoid space. After random allocation, Group 1 received IT fentanyl 50 µg, Group 2 received IT fentanyl 50 µg with nalbuphine 1 mg, and Group 3 received IT fentanyl 50 µg with nalbuphine 2 mg. The total volume was adjusted to 2 ml by the addition of sterile saline. The spinal needle was withdrawn and a 20-g single orifice epidural catheter was inserted 3-4 cm into the epidural space. No additional medication was given until a patient requested it.
RESULTS: Pain scores in the groups were similar before IT opioids were given. At 5 min, all pain scores had decreased to < 3. The mean pain scores in Group 3 were significantly higher at 10 and 15 min than the scores in Group 2 (p=0.003, p=0.008). After 5 min, the overall incidence of pruritus was 76% in Group 1, 57% in Group 2, and 52% in Group 3. Groups 2 and 3 had pruritus scores 3 and fewer incidents of pruritus than did Group 1. The differences were significant from 10 to 30 min (p=0.010, p=0.020, p=0.032). Patient satisfaction scores were significantly higher in Groups 1 and 2 compared to Group 3 at 10, 15 and 30 min.
DISCUSSION: The addition of 1 mg nalbuphine decreased the incidence and severity of pruritus after IT fentanyl and increased patient satisfaction. The 2-mg dose of nalbuphine led to slightly increased pain and sedation ratings. Patients who have experi- enced excessive pruritus from previous intraspinal opioids or patients with skin lesions that would be exacerbated by scratch- ing, may benefit from receiving nalbuphine with IT fentanyl.
REFERENCES:

1. Br J Anaesth 1982; 54:479-86

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