What is the approach to pain management in the emergency room (ER) for patients with acute pain, considering their medical history, current condition, and potential allergies?

Pain Management in the Emergency Department

Immediate Pain Assessment and Triage

All patients presenting to the ED should have pain assessed at triage using validated tools (0-10 numeric rating scale or visual analog scale), and this assessment must be repeated throughout the ED stay to determine treatment effectiveness. 1

• Patients with severe pain (score >7/10) require immediate triage to a treatment room for evaluation and analgesia 1
• Pain scores >3/10 warrant consideration of oral analgesic administration even before full physician evaluation 1
• Reassessment should occur at regular intervals (typically 30-60 minutes after intervention) to guide further treatment 1

First-Line Analgesic Selection by Pain Severity

Mild to Moderate Pain (Score 1-6/10)

For mild-moderate pain, NSAIDs (ibuprofen, naproxen) are superior to codeine-acetaminophen combinations, with a number needed to treat of 2.7 for NSAIDs versus 4.4 for codeine-acetaminophen. 1

• Ibuprofen 400-800 mg PO or ketorolac 30 mg IV/IM provides effective analgesia with longer time to re-medication 1
• Acetaminophen 650-1000 mg PO/IV every 6 hours can be used as monotherapy or combined with NSAIDs 1, 2
• Avoid NSAIDs in patients with aspirin allergy, anticipated surgery, bleeding disorders, renal disease, or post-procedural bleeding risk 1, 2

Moderate to Severe Pain (Score 7-10/10)

For severe acute pain requiring IV opioids, fentanyl (1 mcg/kg initial dose, then ~30 mcg every 5 minutes) is recommended over morphine due to faster onset, shorter duration, and 100-fold greater potency. 1

• Fentanyl has higher lipid solubility resulting in superior bioavailability and more rapid pain relief 1
• Hydromorphone 0.015 mg/kg IV is a comparable or potentially superior alternative to morphine 0.1 mg/kg IV, with quicker onset and less risk of dose-stacking toxicity 1
• If morphine is used, administer 0.1 mg/kg IV slowly (maximum 10 mg), then 0.05 mg/kg at 30 minutes 1, 3
• Rapid IV administration of morphine may cause chest wall rigidity and must be avoided 3

Critical Contraindications and Safety Considerations

Absolute Contraindications to Opioids

• Respiratory depression without resuscitative equipment immediately available 3
• Acute or severe bronchial asthma or hypercarbia 3
• Known or suspected paralytic ileus 3
• Known hypersensitivity to the specific opioid 3

High-Risk Populations Requiring Dose Adjustment

Patients with hepatic cirrhosis or renal failure require significantly lower starting doses of opioids with slow titration and careful monitoring for side effects. 3

• Start with 50% of standard dose in severe renal impairment (CrCl <30 mL/min) 3
• Morphine accumulates active metabolites in renal dysfunction; fentanyl or hydromorphone are preferred alternatives 1, 2
• Elderly patients require lower initial doses due to altered pharmacokinetics and increased sensitivity 4

Drug Allergy Management

Patients with morphine allergies do not have cross-reactivity with fentanyl and can safely receive fentanyl for analgesia. 1

• For NSAID hypersensitivity, challenge with COX-2 inhibitors (celecoxib) is typically tolerated 1
• If specific NSAID allergy is suspected, use an NSAID from a different structural group 1
• Acetaminophen provides safe alternative analgesia without cross-reactivity to NSAIDs 1, 2

Multimodal Analgesia Strategy

Combining analgesics from different mechanistic classes (balanced analgesia) reduces individual drug doses and overall side effect burden while improving pain control. 5, 6

• Acetaminophen 1000 mg IV/PO + ibuprofen 600-800 mg PO provides synergistic analgesia for musculoskeletal pain 1
• For severe pain, combine non-opioid baseline analgesia (acetaminophen + NSAID) with titrated opioid doses 5, 6
• Regional anesthesia techniques (nerve blocks, topical anesthetics) should be considered to minimize systemic analgesic requirements 1

Procedure-Related Pain Control

Topical Anesthesia for Minor Procedures

Topical anesthetics should be applied proactively for any patient with high likelihood of requiring non-emergent invasive procedures on intact skin (IV placement, venipuncture, lumbar puncture, abscess drainage). 1

• Liposomal 4% lidocaine cream (LMX4) provides anesthesia in approximately 30 minutes 1
• Heat-activated systems reduce time required to 10-20 minutes 1
• EMLA cream requires 60 minutes for adequate anesthesia 1

Discharge Analgesia Protocols

Patients discharged from the ED should receive scheduled non-opioid analgesia for 48 hours, then as-needed dosing, rather than opioid-only prescriptions. 2

• Acetaminophen 1000 mg PO every 6 hours scheduled for 48 hours, then PRN 2
• Ibuprofen 600 mg PO every 6 hours with food for 3-5 days for musculoskeletal injuries 1
• If opioids are necessary, prescribe the minimum effective dose for the shortest duration (typically ≤3 days) 7
• All patients on opioids require prophylactic laxative prescriptions to prevent constipation 4

Common Pitfalls to Avoid

• Never delay analgesia pending diagnostic workup - pain control does not mask surgical findings and improves patient cooperation 1
• Avoid combining opioids with benzodiazepines or gabapentinoids outside monitored settings due to compounded respiratory depression risk 4
• Do not use NSAIDs post-endoscopy or in patients with active GI bleeding - they increase bleeding risk and can mask perforation signs 2
• Never administer morphine rapidly IV - slow injection over 4-5 minutes prevents chest wall rigidity 3
• Avoid morphine in elderly or renally impaired patients - active metabolites accumulate causing prolonged sedation and respiratory depression 1, 4

Monitoring and Reassessment Requirements

Pain scores, vital signs, sedation level, and respiratory status must be documented before and after each analgesic intervention. 1

• Reassess pain 30 minutes after oral medication, 15 minutes after IV medication 1
• Monitor for adverse effects including respiratory depression, hypotension, nausea, and altered mental status 3
• Have naloxone immediately available whenever administering opioids 3
• Document pain trajectory and response to treatment in medical record 1