Fentanyl

Question 1

What are the uses of fentanyl?

Answer 1

• periop analgesia
• obtunds hypertensive response to airway manipulation
• opioid based anaesthesia
• sedation by infusion
• chronic pain

Question 2

What is the MOA of fentanyl?

Answer 2

Potent agonist at MOP (mu) receptor

Question 3

What are the effects of fentanyl?

Answer 3

• same as morphine but:
  
  • 50-80x more potent
  • less histamine release
  • decreases stress response to surgery
  • associated with bradycardia
  • chest wall rigidity in high doses

Question 4

What is the absorption/distribution of fentanyl?

Answer 4

• absorption orally from small intestine
• bioavailability 33%
• 80-95% protein bound
• vol of distribution - 0.88 - 4 L/kg
• short duration of action due to distribution

Question 5

What is fentanyl?

Answer 5

• synthetic opioid
• clear colourless solution 50mcg/ml
• patches/lozenges/PCTS (patient controlled transdermal system)

Question 6

What is the dose of fentanyl?

Answer 6

• for induction adjuct (1 - 100mcg / kg)
• pain relief - 1 mcg/kg + repeat to titrate to pain
• spinal 10-30 mcg
• epidural 25 - 100 mcg

Question 7

What are the chemical properties of fentanyl?

Answer 7

• pKa 8.4
• 9% unionized at pH 7.4
• highly ionized in stomach (99.9%)
• highly lipid soluble (600x more than morphine)
• syntehtic phenylpiperidine

Question 8

What is the pKa of fentanyl?

Answer 8

8.4

Question 9

What % of fentanyl is unionized at pH 7.4?

Answer 9

9%

Question 10

What % of fentanyl is plasma protein bound?

Answer 10

84%

Question 11

What is the relative lipid solubility of fentanyl?

Answer 11

580

Question 12

What is the terminal half life of fentanyl?

Answer 12

3.5

Question 13

What is the clearance of fentanyl?

Answer 13

10-15 ml/min/kg

Question 14

What is the volume of distribution of fentanyl?

Answer 14

3-5 L/kg

Question 15

What are the SEs of fentanyl?

Answer 15

• bradycardia
• hypotension
• PONV
• itch
• constipation
• resp depression
• urine retention

Question 16

What is fentanyl?

Answer 16

• synthetic opioid, takes 5 min for effect
• 100 times more potent than morphine
• analgesia lasts 15-30mins

Question 17

What is the does of fentanyl?

Answer 17

• 1-3 mcg/kg at induction
• 2-3 mcg/kg if tubing to decrease response to laryngoscopy

Question 18

What is fentanyl metabolised to?

Answer 18

Inactive products by the liver