Forty-eight Hours of Postoperative Pain Relief after Total Hip Arthroplasty with a Novel, Extended-Release Epidural Morphine Formulation

Abstract

Epidural morphine has proven analgesic efficacy in the postoperative period and is widely used. This study evaluated the efficacy of extended-release epidural morphine (EREM; DepoDur; Endo Pharmaceuticals Inc., Chadds Ford, PA; SkyePharma, Inc., San Diego, CA) in providing pain relief for 48 h after surgery. Patients (n = 200) scheduled to undergo total hip arthroplasty were randomized to receive a single dose of 15, 20, or 25 mg EREM or placebo. After surgery and after asking for pain medication, patients had access to intravenous patient-controlled analgesia fentanyl for breakthrough pain as needed. Postoperative intravenous patient-controlled analgesia fentanyl use, time to first postoperative fentanyl use, pain intensity at rest and with activity, patient and surgeon ratings of pain control, and adverse events were recorded. All EREM dosages reduced the mean (+/- SD) fentanyl use versus placebo (510 +/- 708 vs. 2,091 +/- 1,803 microg; P < 0.0001) and delayed the median time to first dose of fentanyl (21.3 vs. 3.6 h; P < 0.0001). All EREM groups had significantly improved pain control at rest through 48 h postdose (area under the curve [0-48 h]) compared with placebo (P < 0.0005). More EREM-treated patients rated their pain control as good or very good compared with placebo (at 24 h: 90 vs. 65%, P < 0.0001; at 48 h: 83 vs. 67%, P < 0.05). No supplemental analgesia was needed in 25% of EREM-treated patients and 2% of placebo-treated patients at 48 h (P < 0.05). The safety profile of EREM was consistent with that of other epidurally administered opioid analgesics. EREM provided significant postoperative pain relief over a 48-h period after hip surgery, without the need for indwelling epidural catheters.