Acute Pain Management in a Patient with Chronic Kidney Disease
A 72-year-old woman with stage 4 chronic kidney disease (eGFR 25 mL/min/1.73 m²) is admitted with a fractured neck of femur. She is scheduled for hemiarthroplasty under spinal anaesthesia. She weighs 60 kg. Her regular medications include ramipril, atorvastatin, and calcium carbonate. She has no history of opioid use. The acute pain service is asked to recommend an analgesic plan for the perioperative period. She is cognitively intact and able to consent.
1. Which analgesic agents would you choose for this patient and why? Include doses and routes where appropriate.
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For a patient with stage 4 CKD, opioid choice and dose require careful consideration. Morphine is contraindicated due to accumulation of active metabolites (morphine-6-glucuronide) causing prolonged sedation and respiratory depression. Codeine and tramadol should be avoided due to variable metabolism and risk of accumulation. Preferred opioids: fentanyl or oxycodone (with dose reduction). For acute severe pain, titrate IV fentanyl in small aliquots (e.g., 12.5–25 mcg) with monitoring. For ongoing pain, low-dose oxycodone (e.g., 2.5–5 mg orally every 6 hours) may be used with caution, but its active metabolites can accumulate; monitor for sedation. A regional technique such as a fascia iliaca block or femoral nerve block can provide excellent analgesia and reduce opioid requirements. Paracetamol is safe at reduced dose (e.g., 500 mg–1 g every 8 hours, max 2 g/day). NSAIDs are contraindicated. Avoid gabapentinoids due to renal clearance. Multimodal approach with regular paracetamol, regional block, and judicious opioids is recommended.
2. What monitoring and safety measures would you implement to prevent opioid-related harm?
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Implement regular monitoring of sedation (e.g., using the Richmond Agitation-Sedation Scale or Pasero Opioid-Induced Sedation Scale), respiratory rate, and oxygen saturation. Because CKD increases sensitivity to opioids, start with lower doses and extend dosing intervals. Avoid concurrent sedatives. Use a multimodal analgesia regimen to minimise opioid dose. Educate nursing staff and the patient about the risks of sedation and respiratory depression. Consider involving the renal team for medication dose adjustments. If using patient-controlled analgesia (PCA), use fentanyl rather than morphine and ensure appropriate programming with a low background infusion or no background. Daily review of renal function and opioid requirements. Document the plan clearly and communicate with the treating team.