Pediatric Morphine Dosing
The recommended morphine dosing for pediatric patients varies by age, with intravenous doses ranging from 50-100 mcg/kg every 4-6 hours for infants under 3 months to 200-300 mcg/kg every 4-6 hours for children 5-18 years old. 1
Age-Based Dosing Guidelines
Intravenous Administration
- Under 3 months: 50-100 mcg/kg every 4-6 hours 1
- 3-12 months: 100-150 mcg/kg every 4-6 hours 1
- 1-5 years: 150-200 mcg/kg (maximum 10 mg) every 4-6 hours 1
- 5-18 years: 200-300 mcg/kg per single dose, adjusted according to response 1
Oral Administration
- When converting from intravenous to oral morphine, the daily dose should be increased by 2-3 times due to lower bioavailability 1
- Oral morphine at 100 mcg/kg achieves mean peak concentration of 10 mcg/L, with repeat dosing of 100 mcg/kg every 4 hours achieving therapeutic steady-state concentrations of 13-18 mcg/L 2
Clinical Applications
Breakthrough Pain Management
- For breakthrough pain in PACU (Post-Anesthesia Care Unit):
Patient-Controlled Analgesia (PCA)
- Morphine PCA should be administered according to institutional standards based on current literature 1
- Typical PCA settings include:
- Basal infusion: 20 mcg/kg/hour
- Demand dose: 20 mcg/kg
- Maximum doses: 5 doses/hour 4
Special Considerations
Monitoring Requirements
- All patients receiving morphine should have continuous monitoring of vital signs and oxygen saturation 1
- Be prepared to provide respiratory support and administer naloxone for opioid reversal if needed 1
Common Side Effects and Management
- Histamine release with flushing, itching, and hives is common 1
- Increased risk of apnea when combined with other sedative agents, particularly benzodiazepines 1
- For opioid-induced side effects, naloxone infusion at rates ≥1 μg/kg/h can significantly reduce but not eliminate side effects 4
Age-Related Considerations
- Neonates have increased sensitivity to morphine due to immature blood-brain barrier and hepatic metabolism 5
- Factors affecting response to morphine include:
- Concomitant medications (propofol may enhance response)
- Prior opioid exposure (higher 30-day cumulative dose affects response)
- Mechanical ventilation status
- Vasopressor use 6
Practical Administration Tips
- For pain management in clinical practice, normal release morphine should not be given more frequently than every 4 hours 3
- High interindividual variation exists in morphine pharmacokinetics, requiring close monitoring and dose adjustment 3
- When administering morphine for burn pain, larger or more frequent doses may be necessary 1
- For patients with opioid tolerance, dose requirements may be higher 1
Remember that morphine dosing should be carefully titrated based on individual patient response, with close attention to respiratory status and other vital signs, especially in younger children who may be more sensitive to opioid effects.