What is the evidence-based literature for postoperative pain management?

From the Guidelines

The most effective postoperative pain management strategy involves a multimodal approach, including scheduled acetaminophen and NSAIDs, with opioids used as rescue medications, as evidenced by the most recent guidelines from the World Journal of Emergency Surgery in 2022 1.

Key Components of Postoperative Pain Management

• Scheduled acetaminophen (1000 mg every 6 hours, not exceeding 4000 mg daily) is a cornerstone of effective post-op pain control, as it provides a cost-effective strategy to improve outcomes and patient satisfaction with a side-effect profile superior to opioids alone in moderate–severe postoperative pain 1.
• NSAIDs such as ibuprofen (400-600 mg every 6 hours) or HPβCD-diclofenac can be used in a multimodal approach to analgesia, reducing postoperative opioid requirements and improving the quality of pain relief compared to the appointment of each of the drugs separately 1.
• Opioids like oxycodone (5-10 mg every 4-6 hours as needed) or hydromorphone (2-4 mg every 4-6 hours as needed) should be used as rescue medications rather than as scheduled therapy to minimize side effects and dependency risks.

Additional Considerations

• Gabapentinoids such as gabapentin (300-600 mg three times daily) may be beneficial for certain procedures, particularly those with neuropathic pain components, but their use in postoperative management in emergency general surgery is heterogeneous and conflicting 1.
• Regional anesthesia techniques, including nerve blocks with bupivacaine or ropivacaine, can significantly reduce opioid requirements for specific surgeries.
• Early mobilization, proper wound care, and non-pharmacological interventions like ice therapy and elevation complement medication management.

Special Considerations

• Caution is needed in the frail patient, especially in the context of coexisting liver disease, when using acetaminophen, as an increase in alanine aminotransferase has been observed with its use 1.
• The use of coxib is effective in a major surgery context, providing analgesia and opioid-sparing effects, but its combination with NSAIDs seems to increase the incidence of myocardial infarction and affect kidney function 1.
• Ketamine may be considered in severe pain management, with subanesthetic doses having evidence of efficacy in acute pain, but its use should be carefully considered due to potential side effects and contraindications 1.

From the FDA Drug Label

There is no information in the provided drug labels that directly supports the answer to the question about evidence-based literature for postoperative pain management.

The FDA drug label does not answer the question.

From the Research

Postoperative Pain Management

The evidence-based literature for postoperative pain management suggests that a multimodal approach is recommended, combining analgesic drugs from different classes and employing analgesic techniques that target different mechanisms of pain 2, 3, 4, 5. This approach can maximize pain relief at lower analgesic doses, reducing the risk of adverse drug effects.

Non-Opioid Analgesics

Non-opioid analgesics, such as paracetamol, NSAIDs, glucocorticoids, and gabapentinoids, are commonly used in postoperative pain management 6. These drugs have been shown to reduce opioid requirements and opioid-related adverse effects. Specifically:

• Paracetamol reduces 24h post-operative morphine requirements by 6.3mg 6
• NSAIDs reduce 24h post-operative morphine requirements by 10.2mg 6
• Gabapentinoids reduce 24h post-operative morphine requirements by ≥13mg 6

Multimodal Analgesia

Multimodal analgesia is an essential component of Enhanced Recovery after Surgery (ERAS) pathways and protocols, which are becoming the benchmark standards for enhancing postoperative recovery 3. This approach combines different analgesic agents, such as:

• Alpha 2 agonists, which have opioid-sparing effects but can cause hypotension and bradycardia 5
• NMDA receptor antagonists, such as ketamine, which has powerful analgesic effects 5
• Gabapentinoids, which have mixed results in studies but may be beneficial in some cases 6, 5
• Dexamethasone, which reduces postoperative nausea and vomiting and is an effective adjunct in multimodal analgesia 5

Future Directions

There are critical gaps in good quality evidence in many of the practice guideline recommendations, and more research is needed to find the right balance of efficacy and safety 3. Future studies should investigate the use of non-opioid-based drugs and approaches, as well as newer opioid formulations, to improve postoperative pain management. Additionally, genetic testing, derivatives of herbal preparations, and an extended role of acute pain services may emerge as potential areas of importance in the future 3.