What IV analgesics can be safely added for a 74‑year‑old postoperative hip‑replacement patient with opioid use disorder and generalized anxiety who received IV ketorolac two hours ago?

IV Analgesic Options for Post-Hip Replacement Patient with Opioid Use Disorder

For this 74-year-old post-hip replacement patient with opioid use disorder who received IV ketorolac 2 hours ago, IV acetaminophen (paracetamol) should be administered immediately as the next-line agent, followed by IV tramadol if additional analgesia is needed, while avoiding traditional opioids given the substance use history. 1

Immediate First-Line Option: IV Acetaminophen

• IV acetaminophen 1 gram should be administered now and continued every 6-8 hours as the cornerstone of multimodal analgesia 1
• Acetaminophen is specifically recommended to be "better and safer than other drugs" when administered at the beginning of postoperative analgesia 1
• The hip arthroplasty guidelines explicitly recommend paracetamol in combination with NSAIDs (ketorolac already given) as the foundational analgesic regimen 1
• Maximum daily dose is 4 grams (4000 mg), so with 1 gram every 6 hours, you remain well within safe limits 2

Second-Line IV Option: Tramadol

• If acetaminophen alone proves insufficient, IV tramadol can be added as rescue analgesia 1, 3
• Tramadol is specifically recommended in emergency surgery guidelines as appropriate rescue medication when basic analgesics are inadequate 1
• Critical caveat: Assess renal function first—if any renal dysfunction exists, reduce the tramadol dose by 50% 3
• Standard IV tramadol dosing is typically 50-100 mg every 6 hours, but this must be adjusted for age (74 years) and renal status 3
• Tramadol has lower abuse potential compared to traditional opioids, making it more appropriate for patients with opioid use disorder 1

Additional Consideration: IV Dexamethasone

• A single dose of IV dexamethasone 8-10 mg provides both analgesic and anti-emetic benefits 1, 2
• This can be given now if not already administered intraoperatively 1
• Dexamethasone reduces pain scores by more than 20 mm on VAS and decreases opioid requirements 1
• The only concern is a small increase in blood glucose in diabetic patients 1

What to Avoid in This Patient

• Do NOT administer additional ketorolac—the patient received it only 2 hours ago 4
• Ketorolac dosing interval should be every 6 hours minimum, with maximum daily dose of 120 mg and total duration not exceeding 5 days 4
• Traditional IV opioids (morphine, hydromorphone, fentanyl) should be reserved as last-resort options given the opioid use disorder history 1
• If traditional opioids become absolutely necessary, they require enhanced monitoring with sedation scores and respiratory rate assessment 2

Practical Algorithm for This Patient

1. Administer IV acetaminophen 1 gram immediately 1
2. Reassess pain in 30-60 minutes 1
3. If pain remains inadequate (VAS ≥5), check renal function and add IV tramadol 50-100 mg (dose-reduced if renal impairment) 3
4. Consider single dose IV dexamethasone 8-10 mg if not given intraoperatively 1
5. Continue scheduled acetaminophen 1 gram every 6-8 hours 1
6. Ketorolac can be repeated at 6-hour mark from initial dose (4 hours from now) 4
7. Only escalate to traditional IV opioids with patient-controlled analgesia if the above measures fail, with appropriate monitoring 1, 2

Special Considerations for Opioid Use Disorder

• Patients with substance use history may have opioid tolerance requiring higher analgesic doses, but paradoxically may also have opioid-induced hyperalgesia making pain management more complex 1
• The multimodal approach with non-opioid agents is particularly important in this population to minimize opioid exposure 1
• If traditional opioids become necessary, consider acute pain service consultation 1, 3
• Cannabis use status should be assessed, as heavy users (>1.5 g/day smoked) may require increased postoperative analgesia 1

Common Pitfall to Avoid

Do not withhold adequate analgesia based solely on the opioid use disorder diagnosis—undertreated pain leads to worse outcomes including delayed mobilization, increased complications, and paradoxically may trigger substance use relapse 1. The goal is optimized multimodal analgesia that minimizes but does not categorically exclude opioids when medically necessary.