Randomized Double-Blind Trial Comparing Efficacy of Intravenous Nalbuphine vs Intrathecal Nalbuphine for Prevention of Intrathecal Morphine Induced Pruritus in Orthopaedic Surgeries

Intrathecal morphine provides excellent postoperative pain relief but results in pruritus in 30-60% of patients. Nalbuphine, an opioid agonist-antagonist prevents intrathecal morphine-induced itch when given by intravenous route. In this study, we compared efficacy of intrathecal and intravenous nalbuphine for the prevention of intrathecal morphine-induced pruritus. 90 patients were randomly divided into two groups. IT group received 100 mcg of morphine with 400 mcg of nalbuphine intrathecally. IV group received 100 mcg of morphine intrathecally and 400 mcg of nalbuphine intravenously. Incidence of itching, respiratory depression, hypotension, nausea, vomiting, sedation and analgesia were compared between the groups every 4th hourly for 24 hours. Data were analyzed with Chi-square test and Mann-Whitney test. Incidence of itching in 24 hours period was 11.6% (5 patients) in IV group and 4.8% (2 patients) in IT group which was comparable. (P= 0.250) Two patients in IV group had intractable itching requiring naloxone. Incidence of itching at all time intervals was comparable between the groups. Analgesia was prolonged in IV group (P=0.03) Incidence of nausea, vomiting, sedation and respiratory depression was comparable. We conclude that intrathecal nalbuphine and intravenous nalbuphine were equally effective in preventing intrathecal morphine induced pruritus. The duration of analgesia was more when nalbuphine was given by IV route as compared to IT route.