BACKGROUND: The addition of morphine to intrathecal or epidural anesthesia provides an effective, long-lasting postoperative analgesia. However, a common side effect is pruritus which occurs in up to 80 percent of subjects. This study was designed to determine the minimal effective dose of nalbuphine HCI in the treatment and amelioration of morphine-induced pruritus. METHODS: In a prospective, blinded study, 50 patients, 18 to 65 years old who developed pruritus after administration of morphine (intrathecal and epidural) were randomly assigned into 2 groups, Group A received nalbuphine 1 mg/IV every five minutes until pruritus was relieved while Group B received diphenhydramine 50 mg/IV for pruritus. Pruritus scores before and after administration of the drugs were recorded. Data gathered were analyzed using descriptive statistics, students t-test, linear regression and determination of ED50. RESULTS: There was no significant difference between the quality of pain relief between groups A and B. ED50 was noted to occur at 5 mg/IV (the dose in which 50 percent of subjects responded). No significant difference was noted with regards to the ability to relieve pain and the ability to antagonize morphine and its analgesic property. In conclusion, the minimum effective dose of Nalbuphine HCI for amelioration of morphine-induced pruritus is 5 mg per IV. (Author)
Human ; ANESTHESIA ; EPIDURAL, ANESTHESIA ; INTRATHECAL, ANESTHESIA ; ANALGESIA ; ANESTHESIOLOGY ; PRURITUS ; NALBUPHINE HYDROCHLORIDE ; MORPHINE