What medication can be added to oxycodone (opioid analgesic) for an elderly inpatient to help with pain?

Multimodal Analgesia for Elderly Patients on Oxycodone

For elderly inpatients already taking oxycodone, acetaminophen should be added as the first-line adjunctive medication for pain management, administered on a scheduled basis rather than as needed. 1, 2

First-Line Adjunctive Options

• Acetaminophen (oral or IV) should be administered on a scheduled basis (e.g., 500-1000 mg every 6 hours) as the cornerstone of multimodal analgesia in elderly patients 1, 2
• NSAIDs can be added for inflammatory pain components, but must be used cautiously in elderly patients due to increased risk of adverse effects including renal impairment, gastropathy, and cardiovascular complications 1
• Gabapentinoids (gabapentin or pregabalin) are effective adjuncts, particularly for neuropathic pain components, starting at lower doses in elderly patients 1

Second-Line Options

• Tramadol (12.5-25 mg every 4-6 hours) offers dual-mechanism pain relief through opioid and norepinephrine/serotonin reuptake inhibition, providing synergistic effects with oxycodone 1
• Lidocaine patches applied to localized pain areas provide targeted analgesia without significant systemic effects 1, 2
• Low-dose ketamine can be considered as an NMDA receptor antagonist that may help reduce opioid tolerance and provide additional analgesia 1

Opioid Rotation Considerations

• If pain remains inadequately controlled despite adjunctive therapy, consider opioid rotation to hydromorphone, which may be better tolerated in elderly patients with renal impairment 1, 3
• When switching from oxycodone to hydromorphone, use an approximate potency ratio of 1:5-7.5 (hydromorphone is 5-7.5 times more potent than oral morphine, and oxycodone is approximately twice as potent as morphine) 1, 3

Regional Anesthetic Techniques

• For localized pain (especially fracture-related), peripheral nerve blocks should be strongly considered as they can significantly reduce opioid requirements 1, 2
• Regional anesthesia is particularly beneficial in elderly patients as it provides targeted pain relief with minimal systemic effects 1, 2

Important Considerations for Elderly Patients

• Reduce opioid doses by 20-25% per decade after age 55 to minimize adverse effects while maintaining pain control 1
• Monitor closely for drug interactions, as oxycodone can interact with:
  • CNS depressants (benzodiazepines, muscle relaxants) increasing risk of respiratory depression 4
  • Serotonergic drugs potentially causing serotonin syndrome 4
  • Anticholinergic medications increasing risk of urinary retention and constipation 4

Evidence for Combination Therapy

• Adding oxycodone to gabapentin therapy has shown a 33% reduction in pain scores in patients with diabetic neuropathy, with less need for rescue medication and improved sleep 5
• The combination of oxycodone with naloxone has demonstrated effectiveness in elderly patients with chronic pain while reducing opioid-induced constipation 6

Monitoring and Follow-up

• Regularly assess pain control, sedation level, and adverse effects including constipation, confusion, and respiratory status 1, 2
• Monitor for signs of opioid toxicity, which may present atypically in elderly patients (confusion rather than sedation) 1
• Implement bowel regimens prophylactically when using opioids in elderly patients 1

Remember that multimodal analgesia with appropriate adjuncts allows for lower opioid doses, reducing the risk of adverse effects while improving overall pain control in elderly patients 1.