ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Opioid Analgesic Pregnancy: Use with caution; neonatal respiratory depression if given near delivery

Fentanyl

Brand names: Sublimaze, PecFent (intranasal)

Adult dose

Dose: 25-200 micrograms IV (procedural); 200 micrograms intranasal
Route: IV / Intranasal
Frequency: Titrated to effect
Max: As per anaesthetic protocol
Intranasal: 2 micrograms/kg (max 200 micrograms); highly lipophilic — rapid onset 2-3 minutes

Paediatric dose

Dose: 1-2 micrograms/kg IV; 1.5-2 micrograms/kg intranasal micrograms/kg
Route: IV / Intranasal
Frequency: Single dose; may repeat half-dose after 10 min if needed
Max: Intranasal: 200 micrograms total; IV: as per protocol
Intranasal preferred in paediatric ED for needleless analgesia. Use atomiser device (MAD). Onset 2-3 min IN, 1-2 min IV. Duration 30-60 min. Neonates: 0.5-1 microgram/kg with caution — high risk of chest wall rigidity

Dose adjustments

Renal

Reduce dose and increase dosing interval in severe renal impairment

Hepatic

Reduce dose in severe hepatic impairment

Paediatric weight-based calculator

Intranasal preferred in paediatric ED for needleless analgesia. Use atomiser device (MAD). Onset 2-3 min IN, 1-2 min IV. Duration 30-60 min. Neonates: 0.5-1 microgram/kg with caution — high risk of chest wall rigidity

Clinical pearls

  • Antidote: naloxone (IV/IM/intranasal) — shorter duration than fentanyl; repeat doses or infusion may be needed
  • Intranasal fentanyl via MAD device: evidence-based needleless analgesia for fractures and burns in paediatric ED
  • Chest wall rigidity at high IV doses managed with naloxone or suxamethonium and intubation
  • 100x more potent than morphine on a microgram basis — dosing errors can be fatal; double-check doses and units
  • Controlled Drug (CD) — Schedule 2 in UK

Contraindications

  • Respiratory depression (unmonitored)
  • Concurrent MAOI use
  • Neonates without monitoring

Side effects

  • Respiratory depression
  • Muscle rigidity (chest wall — wooden chest at high doses)
  • Nausea and vomiting
  • Bradycardia
  • Hypotension
  • Pruritus

Interactions

  • CNS depressants (additive sedation)
  • MAOIs (serotonin syndrome)
  • CYP3A4 inhibitors (increase fentanyl exposure)

Monitoring

  • Continuous SpO2
  • Respiratory rate
  • Heart rate
  • Level of consciousness
  • Naloxone must be available

Reference: BNF for Children; RCEM Paediatric Pain Guidelines; Borland et al. (2007) intranasal fentanyl evidence. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways