Paediatric Opioid Prescribing

Opioids are used in children for severe acute pain, palliative care and procedural sedation. Dosing is by weight and age, because neonates and young infants have immature clearance and respiratory control and are at much higher risk of respiratory depression.

Choice. Morphine is the usual first-line opioid. Fentanyl is preferred in renal impairment and for rapid short-term use. Codeine and tramadol are avoided. Oxycodone is an alternative where available.

• Morphine oral (1 to 12 years): 0.2 to 0.3 mg/kg every 4 hours; infants 3 to 12 months 0.1 to 0.2 mg/kg every 4 to 6 hours; neonates and infants under 3 months 0.05 mg/kg every 6 hours (specialist).
• Morphine intravenous bolus: 0.05 to 0.1 mg/kg titrated slowly every 10 to 15 minutes; neonates 25 to 50 mcg/kg.
• Morphine infusion: loading 0.1 mg/kg, then 10 to 30 mcg/kg/h in older infants and children; 5 to 20 mcg/kg/h in neonates and ventilated infants.
• Patient-controlled analgesia: morphine bolus 10 to 20 mcg/kg, lockout 5 to 10 minutes, background 0 to 4 mcg/kg/h. Suitable from about 5 to 6 years. Nurse-controlled analgesia is used in younger children.
• Fentanyl: 1 to 2 mcg/kg intravenous bolus given slowly (rapid bolus causes chest wall rigidity), infusion 1 to 4 mcg/kg/h, intranasal 1.5 mcg/kg once (maximum 100 mcg).
• Naloxone for respiratory depression: 4 to 10 mcg/kg intravenously, titrated and repeated every 2 to 3 minutes; for respiratory arrest 100 mcg/kg (maximum 2 mg). The effect is shorter than that of most opioids, so an infusion or repeated dose may be needed.

Prevent predictable effects. Give a stimulant or osmotic laxative (macrogol or lactulose) with regular opioids. Treat nausea with ondansetron 0.1 to 0.15 mg/kg intravenously (maximum 4 mg) and pruritus with a low-dose naloxone infusion or a non-sedating antihistamine.

Kidney impairment. Morphine-6-glucuronide accumulates, so reduce the dose by 25 to 50% or use fentanyl.

Liver impairment, sleep apnoea and head injury. Reduce dose, lengthen intervals and avoid in obstructive sleep apnoea unless monitored closely.

Concurrent sedatives. Benzodiazepines, gabapentinoids and sedating antihistamines add respiratory risk and need dose reductions and closer monitoring.

Special groups. Breastfed infants of mothers on opioids need observation. Infants exposed to long-term opioids need a weaning plan, usually reducing by 10 to 20% every 1 to 2 days. In East Africa, oral morphine is the main option, and sickle cell pain should not be undertreated for fear of dependence.

Monitoring. Record respiratory rate, oxygen saturation and a sedation score every hour for the first 4 hours after starting, then every 2 to 4 hours. Hold the dose and review if the child is difficult to rouse, respiratory rate is under 20 breaths/min in infants or under 10 breaths/min in older children, or saturation is under 94%.

Referral and escalation. Seek senior or pain team input for infusions, patient-controlled analgesia, neonates and any child needing escalating doses.

Stopping. After more than 5 days of continuous use, taper by 10 to 20% every 1 to 2 days and watch for withdrawal (irritability, tachycardia, sweating, diarrhoea).