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Opioid (Ultra-Short-Acting) Pregnancy: C — crosses placenta; neonatal respiratory depression if not stopped before delivery

Remifentanil

Brand names: Ultiva

Adult dose

Dose: Induction: 0.5–1 microgram/kg/min. Maintenance: 0.05–2 mcg/kg/min (TCI or manual). Awake craniotomy: 0.04–0.2 mcg/kg/min
Route: IV infusion only
Frequency: Continuous infusion
NOT for bolus administration outside intubation setting. Always use with propofol or volatile agent. Must ensure alternative analgesia before stopping — NO residual effect.

Paediatric dose

Dose: 0.05 mcg/min/kg
Route: IV infusion
Frequency: Continuous (maintenance)
Children ≥1 year: 0.05–1 mcg/kg/min. Neonates: 0.03–0.06 mcg/kg/min. Higher infusion rates (up to 4 mcg/kg/min) during stimulation.
Paediatric weight-based calculator

Children ≥1 year: 0.05–1 mcg/kg/min. Neonates: 0.03–0.06 mcg/kg/min. Higher infusion rates (up to 4 mcg/kg/min) during stimulation.

Clinical pearls

  • Unique: metabolised by non-specific plasma and tissue esterases — NOT dependent on liver or kidney
  • Half-life ~3–5 minutes regardless of duration of infusion — context-insensitive half-life
  • CRITICAL: plan post-operative analgesia BEFORE stopping infusion — complete offset in minutes
  • Opioid-induced hyperalgesia (OIH): prolonged high-dose infusion may increase post-op pain sensitivity
  • Ideal for neurosurgery, cardiac surgery, and day-case procedures requiring rapid recovery

Contraindications

  • Epidural or intrathecal administration (glycine-containing formulation — toxic to CNS)

Side effects

  • Respiratory depression
  • Bradycardia
  • Hypotension
  • Chest wall rigidity (high doses/rapid bolus)
  • Opioid-induced hyperalgesia (OIH) with prolonged infusion
  • NO residual analgesia on stopping

Interactions

  • Propofol — reduce both doses (synergy)
  • CNS depressants — additive effects

Monitoring

  • SpO2 and ETCO2 (mandatory during infusion)
  • Blood pressure and heart rate (continuous)
  • Respiratory rate post-operatively

Reference: BNFc; BNF; Miller's Anesthesia; AAGBI TCI Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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