A 68-year-old female is started on opioid therapy for pain c…

A 68-year-old female is started on opioid therapy for pain control after admission for an automobile accident. Her pain was well controlled until the last 2 days when she developed increased somnolence and decreased respiratory rate, leading to intubation. There were no changes in her medication therapy. Current labs include Na: 135 meq/L; K 5.2 meq/L; Cl: 119 meq/L; BUN: 40; and SCr: 4.5 mg/dL, total bilirubin = 2.4. Which opioid would be the most appropriate to use in this patient?