Postoperative Pain After Laparotomy

Patient B-217 is a 55-year-old man, weight 80 kg, on day 2 after an elective laparotomy. He is currently nil by mouth. He reports severe abdominal pain, scoring 8/10 on a numeric rating scale. His heart rate is 98 bpm, blood pressure 135/80 mmHg, respiratory rate 22 breaths per minute, oxygen saturation 96% on air, temperature 37.2°C. On abdominal examination, the wound is clean and dry, the abdomen is soft but tender around the incision, with no guarding or rigidity. Bowel sounds are present. He has no known drug allergies. Before surgery he was taking oral modified-release morphine 30 mg twice daily for chronic low back pain. His regular medicines also include amlodipine 5 mg once daily. He has not received any opioid since his surgery. Renal function today: serum creatinine 1.7 mg/dL, eGFR 45 mL/min/1.73 m². Liver function tests are normal. The surgical team asks you to prescribe his analgesia: a regular opioid, a breakthrough opioid for breakthrough pain, an antiemetic, and a laxative. He is to remain nil by mouth for the next 24 hours.