Aprepitant vs. Multimodal Prophylaxis in the Prevention of Nausea and Vomiting following Extended-Release Epidural Morphine

Background: Extended-release epidural morphine (EREM) is an effective option for postoperative analgesia following major orthopedic surgery; however, postoperative nausea/vomiting (PONV) is a recognized limitation. The incidence of PONV following prophylactic aprepitant, a neurokinin-1 antagonist, was compared with prophylactic multimodal antiemetic therapy in patients receiving EREM for postoperative analgesia following unilateral primary total knee arthroplasty (TKA). Methods: Prospectively collected quality assurance data were examined with Institutional Review Board approval. A sequential, open-label, active matched case-control study compared PONV following EREM in patients receiving ondansetron and dexamethasone, and either metoclopramide, diphenhydramine, or prochlorperazine every 6 hours for the 48-hour study period, to patients receiving aprepitant 40 mg given as a single oral dose in the preoperative holding area. Cases were matched for procedure (TKA), age, epidural morphine dose, and known major risk factors for PONV (sex, smoking, previous PONV/motion sickness). Results: Twelve consecutive patients (3 male; 9 female) receiving aprepitant prior to EREM were matched to 12 patients of the same sex of similar age (range 51 to 84 years.) and EREM dose (range 5 to 12.5 mg) receiving the multimodal regime. The incidence of PONV was significantly less for the aprepitant group where 3 of 12 (25%) had PONV compared with 9 of 12 (75%) in the multimodal group (P = 0.039, Fisher's Exact Test; odds ratio = 0.11; 95% CI: 0.018 to 0.706, P = 0.03). Conclusion: While aprepitant significantly reduced the incidence of PONV compared with a multimodal antiemetic regime, used alone it did not eliminate PONV.