What is the best opioid for pain management in pediatric patients under 18 years old, specifically those under 2 years old?

Best Opioid Selection for Pediatric Patients

For infants under 2 years old, intravenous nalbuphine is the preferred opioid for rescue analgesia, while intravenous fentanyl is recommended for breakthrough pain in acute settings; for children 2-18 years old, oral/rectal/intravenous tramadol is the first-line opioid for ward-based pain management, with fentanyl reserved for acute breakthrough pain. 1

Age-Specific Opioid Recommendations

Infants Under 2 Years Old

Acute/Breakthrough Pain (PACU Setting):

• Intravenous fentanyl is the primary opioid for treating serious breakthrough pain in the post-anesthesia care unit 1
• Fentanyl should be administered in divided doses and titrated to effect 1

Ward-Based Rescue Analgesia:

• Intravenous nalbuphine is specifically recommended as the rescue opioid for infants 1
• The guidelines explicitly state "In infants, for older children available opioid of choice" when discussing nalbuphine, indicating it is the preferred agent for this age group 1

Critical Safety Consideration:

• Opioids in infants increase the risk of postoperative respiratory impairment and should be used with caution 1
• Adequate monitoring (pulse oximetry and clinical observation) is mandatory when administering any opioid to infants 1

Children 2-18 Years Old

Ward-Based Pain Management:

• Oral, rectal, or intravenous tramadol is the recommended first-line opioid for postoperative pain management on the ward 1
• Tramadol can be administered through multiple routes, providing flexibility based on clinical circumstances 1

Acute/Breakthrough Pain (PACU Setting):

• Intravenous fentanyl remains the opioid of choice for treating breakthrough pain in acute settings 1
• Alternative suitable agents may be used if available, but fentanyl is the standard 1

Intraoperative Options:

• Fentanyl: 1-2 micrograms/kg 1
• Morphine: 25-100 micrograms/kg (titrated to effect, age-dependent) 1
• Sufentanil: 0.5-1 micrograms/kg bolus 1
• Remifentanil: continuous infusion (though controversial due to potential postoperative hyperalgesia) 1

Absolute Contraindications

Codeine is contraindicated in ALL children under 12 years old per FDA boxed warning issued in 2017 2. This applies to:

• All codeine-containing products regardless of formulation 2
• Treatment of both pain and cough 2
• The contraindication exists due to 21 reported deaths in children under 12 from respiratory depression related to ultra-rapid metabolism 2

Codeine should also be avoided in adolescents 12-18 years who are obese or have obstructive sleep apnea 2. The American Academy of Pediatrics and American Academy of Otolaryngology strongly recommend against codeine use in children 2.

Multimodal Approach to Minimize Opioid Use

The European Society for Paediatric Anaesthesiology emphasizes that opioids should be part of a multimodal strategy, not monotherapy 1:

Non-Opioid Foundation:

• NSAIDs (ibuprofen, naproxen, ketorolac) throughout the postoperative period 1
• Paracetamol (acetaminophen) via oral, rectal, or intravenous routes 1
• The combination of NSAIDs and paracetamol has opioid-sparing effects 1

Regional Anesthesia Priority:

• Regional blocks with long-acting local anesthetics should be prioritized whenever possible 1
• This approach can allow total avoidance of opioids in certain procedures 1

Adjunctive Agents:

• Intraoperative ketamine has opioid-sparing effects and reduces respiratory impairment risk 1
• Alpha-2 agonists (clonidine) reduce opioid requirements and postoperative agitation 1

Monitoring Requirements

All opioid administration in pediatric patients requires:

• Minimum: pulse oximetry and clinical observation 1
• Preferably: high to intermediate care setting for 24-48 hours after major operations 1
• Experienced staff available around the clock, ideally an Acute Pain Service team 1

Common Pitfalls to Avoid

Do not use codeine even if a child has previously received it without apparent adverse effects, as metabolism is unpredictable and safer alternatives exist 2.

Do not rely on opioids alone - the multimodal approach with NSAIDs, paracetamol, and regional anesthesia significantly reduces opioid requirements and associated complications 1.

Do not forget PONV prophylaxis - opioid administration increases postoperative nausea and vomiting risk, and prophylaxis is highly recommended 1.

Avoid remifentanil without transition planning - if using continuous remifentanil intraoperatively, administer a longer-acting opioid toward the end of the procedure to prevent an analgesic gap 1.