What is the stepwise approach for acute pain management?

Acute Pain Management Algorithm

For acute pain management, begin with noninvasive nonpharmacologic approaches and nonopioid medications as first-line therapy, escalating to opioids only for severe pain or when initial measures fail, following a structured stepwise approach based on pain intensity. 1

Step 1: Initial Assessment and Diagnosis

Evaluate pain severity using standardized self-report tools:

• Ask specifically: "What has been your worst pain in the last 24 hours on a scale of 0-10?" where 0 is no pain and 10 is the worst imaginable pain 2
• Use visual analogue scales (VAS), numerical rating scales (NRS), or verbal rating scales (VRS) for comprehensive assessment 1, 2
• Document onset, quality, intensity, location, duration, exacerbating and relieving factors 2
• Assess impact on daily activities, sleep, mood, and quality of life 2
• Identify the underlying cause to guide disease-specific treatment 3

For patients with cognitive impairment:

• Observe behavioral indicators including facial expressions, body movements, and vocalizations 2

Step 2: Mild Pain (Pain Score 1-4)

First-line: Noninvasive nonpharmacologic approaches 1

• Ice and elevation for musculoskeletal injuries to reduce swelling 1
• Heat therapy for acute low back pain 1
• Massage for postoperative pain 1
• Acupressure for acute musculoskeletal pain 1
• Spinal manipulation for acute back pain with radiculopathy 1

First-line pharmacologic: Nonopioid analgesics 1, 2

• Acetaminophen/paracetamol: Maximum 4,000 mg/day 2, 4
  • Use lower doses in patients with advanced liver disease, malnutrition, or severe alcohol use disorder 4
• NSAIDs: 1, 2
  • Topical NSAIDs provide the greatest benefit-harm ratio for musculoskeletal injuries (sprains, whiplash, muscle strains) 1, 4
  • Oral NSAIDs: Ibuprofen 400 mg is the safest option 5
  • Provide gastroprotection when NSAIDs are used for prolonged periods 1
  • Use with caution in patients with history of GI bleeding, cardiovascular disease, or chronic kidney disease 4

Condition-specific first-line agents:

• Dental pain: NSAIDs as first-line 1
• Kidney stone pain: NSAIDs preferred over opioids (decrease ureteral smooth muscle tone and spasm) 1
• Low back pain: NSAIDs or skeletal muscle relaxants 1
• Migraine: Triptans, NSAIDs, antiemetics, dihydroergotamine, or acetaminophen 1

Step 3: Moderate Pain (Pain Score 5-7)

Add weak opioids to nonopioid analgesics 1, 2

• Codeine, dihydrocodeine, or tramadol combined with acetaminophen or NSAIDs 1, 2
• Maximum doses: 4,000 mg acetaminophen and 240 mg codeine 1
• Alternative: Low doses of strong opioids (morphine or oxycodone) 1, 2

Consider adjunctive medications:

• Muscle relaxants for acute low back pain 1, 4
• Multimodal analgesia to decrease total opioid requirements 1

Step 4: Severe Pain (Pain Score 8-10)

Strong opioids are indicated 1, 2

• Morphine is the most commonly used and preferred agent 1, 2
• Alternatives: Hydromorphone, oxycodone (both available in immediate and controlled-release formulations) 1
• Transdermal fentanyl: Reserved for patients with stable opioid requirements, unable to swallow, poor morphine tolerance, or poor compliance 1

Opioid administration principles:

• Oral route is preferred 1
• Parenteral dosing is 1/3 of oral dose 1
• Scheduled dosing around-the-clock for persistent pain rather than "as needed" 1, 2
• Provide rescue doses (10-15% of total daily dose) for breakthrough pain 2, 6
• Titrate rapidly to achieve effective pain control 2
• Adjust baseline regimen if more than four rescue doses are needed daily 2, 6

Avoid these medications:

• Mixed agonist-antagonists (pentazocine, nalbuphine, butorphanol) as they may precipitate withdrawal in opioid-tolerant patients 1, 6
• Fixed-dose acetaminophen/opioid combinations in patients requiring high doses (risk of hepatotoxicity) 1, 6

Step 5: Adjuvant Therapies

For neuropathic pain components:

• Anticonvulsants (gabapentin, pregabalin) 2
• Antidepressants (tricyclics, SNRIs) 1, 2
• Corticosteroids 2

To enhance opioid effects:

• Tricyclic antidepressants 1

Step 6: Special Population - Patients on Methadone/Buprenorphine

Critical principles:

• Continue the usual maintenance dose without interruption 1, 6
• Add short-acting opioids (morphine, hydromorphone, oxycodone) at higher doses and shorter intervals than for non-tolerant patients 1, 6
• Reassure patients that maintenance treatment will continue and pain will be aggressively treated 1
• Use scheduled dosing rather than as-needed to prevent pain recurrence 1
• Consider patient-controlled analgesia to minimize anxiety 1, 6
• Never use mixed agonist-antagonists (will precipitate withdrawal) 1, 6

Step 7: Monitoring and Follow-up

Ongoing assessment:

• Evaluate pain at every contact or at least daily for hospitalized patients 2
• Reassess both pain and analgesic side effects regularly 2
• Review and adjust the regimen if side effects persist or pain remains uncontrolled 2
• Provide written pain management plan including prescribed medications 2

Opioid safety:

• Prescribe the shortest duration necessary for acute pain 1
• If opioids are used around-the-clock for more than a few days, taper when discontinuing 1
• Ensure patients understand benefits, risks, and alternatives before starting opioids 1

Critical Pitfalls to Avoid

• Underestimating pain severity in cognitively impaired patients 2
• Undertreating acute pain, which may lead to decreased opioid responsiveness and more difficult subsequent pain control 1
• Allowing pain to recur before administering the next dose, causing unnecessary suffering and patient-provider tension 1
• Confusing therapeutic dependence (drug-seeking to maintain comfort) with addiction 1
• Interrupting maintenance opioid therapy in patients on methadone/buprenorphine 1, 6
• Failing to recognize that many patients have multiple pain types requiring different approaches 2