FENTANYL 

 1. Introduction

• Synthetic μ-opioid receptor agonist
• Highly lipophilic → rapid CNS penetration
• ~100 times more potent than morphine
• Preferred ICU opioid due to:
• Hemodynamic stability
• Minimal histamine release
• Rapid onset

 2. Pharmacology

 Mechanism of Action

• Acts on μ-opioid receptors (G-protein coupled)

Result:

• Analgesia
• Sedation (mild)
• Respiratory depression

Pharmacokinetics

• Accumulates in fat tissues → prolonged sedation in long infusions

 3. Pharmacodynamics

4. ICU Indications 

Analgesia (Primary use)

• Post-operative ICU patients
• Trauma
• Burns
• Cancer pain

 Sedation adjunct

• Used with:
• Propofol
• Midazolam

 Mechanical ventilation

• Improves:
• Ventilator synchrony
• Tolerance to ETT

 Hemodynamically unstable patients

• Preferred over morphine (no histamine release)

 Procedural analgesia

• Intubation
• Central line insertion

 5. Dosing in ICU 

 Bolus Dose in Adult

• 25–100 mcg IV (repeat as needed)

 Infusion Dose

• 1–3 mcg/kg/hr (typical)
• Severe pain → up to 5 mcg/kg/hr

 SCCM PADIS recommendation:

• Opioid-first analgesia strategy preferred

 6. Adverse Effects 

 Respiratory

• Respiratory depression
• Apnea

 Chest Wall Rigidity (“Wooden Chest Syndrome”)

• Seen with:
• High doses
• Rapid IV push
• Causes:
• Difficult ventilation

 Management:

• Naloxone
• Neuromuscular blockade

 CNS

• Sedation
• Delirium (ICU)

GIT

• Ileus
• Constipation

 CVS

• Bradycardia

 Tolerance & Dependence

• Common in prolonged ICU stay

 7. Comparison with Other Opioids

 8. Reversal

• Drug: Naloxone
• Dose:
• 0.04–0.4 mg IV (titrate)

 Risk:

• Acute withdrawal
• Re-sedation (short duration vs fentanyl)

 9. Guidelines & Evidence 

 SCCM PADIS Guidelines

• Opioids preferred over sedatives for pain control
• Avoid deep sedation
• Use analgesia-first sedation strategy

 ERAS Protocols

• Fentanyl widely used but:
• Preference shifting toward shorter-acting opioids (remifentanil)