TREATMENT OF INTRATHECAL MORPHINE-INDUCED PRURITUS FOLLOWING CESAREAN-SECTION

Purpose: To compare both the efficacy and cost of nalbuphine and diphe nhydramine in the treatment of intrathecal morphine-induced pruritus f ollowing Caesarean section. Methods: Eighty patients, undergoing elect ive Caesarean section under spinal anaesthesia, were randomized, in a prospective, double-blind trial, to receive either nalbuphine (Group N AL) or diphenhydramine (Group DIP) for the treatment of SAB morphine-i nduced pruritus. Al patients received an intrathecal injection of 10-1 2 mg hyperbaric bupivacaine 0.75% and 200 mu g preservative free morph ine, Postoperative pruritus was assessed, using a visual analogue scal e (VAS), for 24 hr, Pruitus treatment was administered upon patient re quest and by a nurse blinded to the treatment given, Patients who fail ed to respond to three doses of the study drug were deemed treatment f ailures. Patient satisfaction was assessed with a questionnaire given 24 to 48 hr after surgery. Direct drug costs were calculated based on the pharmacy provision costs as of April 1996.Results: Eighty patients were enrolled and 45 requested treatment for pruritus. Patients treat ed with NAL (n = 24) were more likely to achieve a VAS score of zero w ith treatment (83% vs 43%, P < 0.01), had a higher Delta VAS following treatment (4 +/- 2 vs 2 +/- 2, P < 0.003), and experienced fewer trea tment failures (4% vs 29%, P < 0.04), than those treated with DIP (n = 2 1). Group NAL patients were also more likely to rate their pruritus treatment as being good to excellent (96% vs 57%, P < 0.004). Direct drug costs were higher for NAL than for DIP ($6.4 +/- 3.1 vs $1.7 +/- 0.7, respectively, P < 0.0001). Conclusion: Nalbuphine is more effecti ve than diphenhydramine in relieving pruritus caused by intrathecal mo rphine and the cost differences are small.