Abstract
Extended-release epidural morphine (EREM) provides effective postoperative analgesia for 48 h following injection. It is administered as a single bolus into the lumbar epidural space, and is indicated for lower abdominal and lower extremity surgery associated with moderate-to-severe pain. While its efficacy has been well documented in randomized controlled trials, the safety and clinically appropriate dosing are less well defined. A meta-analysis approach was used to assess the adverse effects of EREM (n = 801) in comparison with intravenous opioids and standard epidural morphine. EREM 15 mg or greater was associated with a trend towards a higher incidence of hypoventilation (odds ratio: 0.48; 95% confidence interval [CI]: 0.21–1.09; p = 0.081; number-needed-to-treat [NNT] = 14) compared with placebo. The incidence of pruritus was significantly higher for all EREM doses compared with both placebo (p = 0.004) and standard epidural morphine (p = 0.03). Vomiting was also increased with EREM 15 mg or greater compared with placebo (odds ratio: 0.40; 95% CI: 0.18–0.89; p = 0.02; NNT = 5). A multimodal analgesic regime is recommended to permit the use of lower EREM doses, thus reducing the risk for adverse effects including respiratory depression. Prophylactic time-contingent antiemetics are also recommended when EREM is used.
Financial & competing interests disclosure
CT Hartrick has received research support in the past from DepoTech, SkyePharma and Endo Pharmaceuticals. No support or assistance of any kind was provided for this analysis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.