Fentanyl - IV

Question 1

What is the brand/trade name for fentanyl?

Answer 1

• Sublimaze

Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1

DrugBank Online - Fentanyl

Question 2

What is the pharmacologic category/class of fentanyl?

Answer 2

• Opioid Analgesic — Synthetic
• Phenylpiperidine

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 4. Classification, Relative Potency & Opioid Abuse

UpToDate - Fentanyl: Drug Information

Question 3

What is the mechanism of action of fentanyl?

Answer 3

Opioid rececptor agonism, especially mu, with resultant increase in pain threshold, altered pain perception, and inhibition ascending pain pathways

• Presynaptic: decreases cAMP-dependent influx of calcium ions → inhibition of neurotransmitter release
• Post synaptic: increased outward K⁺ conductance → hyperpolarization of nerve cell

Note that these are similar to those of other opioids

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 2. Opioid Receptors

DrugBank Online - Fentanyl

Nagelhout (7th ed.), pp. 141 - Fig. 11.2, 142, 1295-1296, 1298

Stoelting’s Pharmacology (5th ed.), pp. 218-219

Question 4

The experience of pain can be divided into four steps: transduction, transmission, modulation, and perception. Which of these does fentanyl have an effect on?

Answer 4

Along with other opioids, fentanyl effects

• transduction
  _{peripheral nerves}
• modulation
  _{spinal cord}
• perception
  _{brain/brainstem}

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 1 & 2

Question 5

When used as an adjunct during induction and intubation what dose of fentanyl is used?

Answer 5

• 1-3 mcg/kg IV

This helps to blunt the SNS response

Dosing is similar for pediatrics

Stoelting’s Pharmacology (5th ed.), p. 232

UpToDate - Fentanyl: Drug Information

Question 6

What is the typical dose of fentanyl for procedural sedation and analgesia?

Emphasis because ranges may vary depending on patient/procedure

Answer 6

• 0.5-1 mcg/kg IV

repeated as often as every 2-15 minutes to achieve desired level of sedation/analgesia — continuous infusion is also an option

Dosing is similar for pediatrics

Stoelting’s Pharmacology (5th ed.), p. 232

UpToDate - Fentanyl: Drug Information

Question 7

What is the onset of action for fentanyl?

Answer 7

• “Rapid/immediate” with maximal effects in 2-5 minutes

Nagelhout (7th ed.), p. 1298

Stoelting’s Pharmacology (5th ed.), p. 231

UpToDate - Fentanyl: Drug Information

Question 8

What is the duration of action for fentanyl?

Answer 8

• 30-60 minutes

Duration related to rapid redistribution to inactive tissue sites

Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1

UpToDate - Fentanyl: Drug Information

Question 9

What organ(s) are responsible for fentanyl’s clearance (metabolism/elimination)?

Answer 9

• Metabolism: Liver (P450)
• Elimination: Kidneys

Half-life: ~3-6 hrs — due to sequestration in tissues

Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1

UpToDate - Fentanyl: Drug Information

Question 10

As an analgesic, fentanyl is __________ times more potent than morphine

Answer 10

• ~100

This number varies slightly between texts

Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 4. Classification, Relative Potency & Opioid Abuse

Question 11

Cardiovascular effects of fentanyl include:

Answer 11

• Bradycardia
• Stable SVR/MAP
  _{no histamine release}

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 2 & 3

Stoelting’s Pharmacology (5th ed.), p. 233

Question 12

What are the respiratory effects of fentanyl?

Answer 12

• Dose dependent depression of ventilation — RR affected before Vt
  _{(shifting of the CO2 response curve)}
• Inhibits hypoxic ventilatory drive
• Apnea at large doses

Note that these are similar to those of other opioids

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 2 & 3

Nagelhout (7th ed.), p. 142

Stoelting’s Pharmacology (5th ed.), p. 222

Question 13

What are the effects of fentanyl on the CNS?

Answer 13

• Sedation
• Miosis/pinpoint pupils
• Mild hypothermia
  _{resets hypothalamic temperature setpoint}
• N/V
  _{Partial dopamine agonists at CTZ}

Note that these are similar to those of other opioids

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 2 & 3

Nagelhout (7th ed.), p. 142

Stoelting’s Pharmacology (5th ed.), p. 222

Question 14

What are the GI/GU effects of fentanyl?

Answer 14

• Slowed peristalsis → CONSTIPATION
• N/V
• Contraction of sphincter of Oddi → biliary colic
  _{evidence is kind meh on this}
• Delayed gastric emptying
• Urinary retention (IDGAF)
  _{detrusor relaxation, urinary sphincter constriction}

Note that these are similar to those of other opioids

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 2 & 3

Nagelhout (7th ed.), pp. 143-144

Stoelting’s Pharmacology (5th ed.), pp. 223-224

Question 15

Rapid IV administration of large doses of opioids, particularly fentanyl and its derivatives, can lead to generalized ______________; the greatest impact is on the ability to ______________

Answer 15

• Skeletal muscle rigidity
• Ventilate

_{some decrease in chest wall compliance, but this is mostly related to constriction of laryngeal musculature}

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 10. Skeletal Muscle Rigidity

Nagelhout (7th ed.), pp. 143-144

Stoelting’s Pharmacology (5th ed.), p. 223

Question 16

BONUS

True or false:

• Fentanyl is more hydrophilic than morphine

Answer 16

• False

_{Fentanyl is more lipophilic, as evidenced by some of it’s pharmacokinetic and pharmacodynamic characteristics}

Nagelhout (7th ed.), p. 147

Stoelting’s Pharmacology (5th ed.), p. 231

Question 17

Why is fentanyl preferred over morphine in patients with renal failure?

Answer 17

• It’s metabolites are inactive

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 5. Metabolism

Nagelhout (7th ed.), p. 147

Question 18

What is the concentration (mg/mL) of fentanyl vials?

Answer 18

• 50 mcg/mL

UpToDate - Fentanyl: Drug Information