Fentanyl

Question 1

What is the drug class of Fentanyl?

Answer 1

synthetic phenylpiperidine opioid agonist, analgesic

Question 2

What are the uses of Fentanyl?

Answer 2

• Analgesia intraop and postop
• administered as premed to blunt hemodynamic responses to airway manipulation and reduce inhalation agent dosage requirements
• provides GA either administered as sole anesthetic or in combo with IV sedatives/hypnotics
• administered in the epidural and subarachnoid spaces to augment the effectiveness of RA

Question 3

What is the MOA of Fentanyl?

Answer 3

• Binds to mu opioid receptors in the brain, brainstem, spinal cord, and primary afferent peripheral terminals producing analgesia
• mimics the actions of enkephalins, endorphins, dynorphins causing the action of antinocioceptive systems resulting in cellular hyperpolarization and inhibition of NT release

Question 4

How is Fentanyl metabolized?

Answer 4

primarily in the liver by N-dealkylation and Hydroxylation

-dependent on liver blood flow/ high hepatic extraction ratio

Question 5

Does metabolism of Fentanyl produce metabolites?

Answer 5

-minimally pharmacologically active metabolites: Norfentanil, hydroxyproprionyl-fentanyl, and hydroxyproprionyl-norfentanyl

Question 6

How is Fentanyl redistributed?

Answer 6

• Fentanyl is highly lipid soluble allowing rapid crossing of biological membranes and uptake by highly perfused tissue groups including the brain, heart, lungs
• Rapidly redistributed to inactive tissue sites such as fat and muscle

Question 7

What is important about the lungs and Fentanyl?

Answer 7

The lungs serve as a large inactive storage site, with an estimated 75% of the initial dose undergoing 1st pass pulmonary uptake

Question 8

What is the Volume of Distribution?

Answer 8

Vd is 4L/kg

Question 9

What is the distribution time? redistribution time?

Answer 9

Distrib time: 1.7 minutes

Redistribution time: 13 minutes

Question 10

What is the termination elimination 1/2 time of Fentanyl?

Answer 10

3.1 - 6.6 hours

Question 11

How is Fentanyl eliminated?

Answer 11

Norfentanyl (principle metabolite) excreted by the kidneys and can be detected in the urine 48 - 72 hours after administration

Question 12

Is Fentanyl protein bound?

Answer 12

approx 80% protein bound to plasma proteins

Question 13

What are the CNS side effects of Fentanyl?

Answer 13

• increase in ICP in head injury patients if respiration is not controlled
• seizure like activity and muscle rigidity
• Dizziness, blurred vision
• Miosis
• Pruritis
• Drowsiness, Sedation, Confusion
• CNS depression

Question 14

What are the CV effects of Fentanyl?

Answer 14

• Bradycardia
• Elevated CVP, PAP, and PVR associated with opioid induced muscle rigidity, hypotension, peripheral vasodilation, arrythmia

Question 15

What are the respiratory effects of Fentanyl?

Answer 15

• Respiratory depression
• depression of airway reflexes
• decreased lung compliance, FRC, hypercapnia, and hypoxemia associated with opioid induced muscle rigidity
• Bronchospasm
• Laryngospasm

Question 16

What are the GI effects of Fentanyl?

Answer 16

• increased common bile duct pressure
• N/V
• Delayed gastric emptying and intestinal transit

Question 17

What are the endocrine/metabolic effects of Fentanyl?

Answer 17

ADH release

Question 18

What are the contraindications to use of Fentanyl?

Answer 18

-use with caution in patients with impaired hepatic and/or renal function, head trauma, elevated ICP, and bradyarrhythmias

Question 19

What synergistic effect occurs with Fentanyl and ____________ and __________?

Answer 19

Benzodiazepines and other CNS depressants cause marked opioid synergism with respect to hypnosis and respiratory depression

Question 20

What drug interaction can occur between Fentanyl and Nitrous Oxide?

Answer 20

cardiovascular depression

Question 21

Adminstration with _________ and Fentanyl may cause?

Answer 21

Droperidol

may cause hypotension or HTN

Question 22

What is the anesthetic premedication dose of Fentanyl?

Answer 22

25 - 100 mcg

Question 23

What is the analgesia (including post-op bolus) dose of Fentanyl?

Answer 23

1 - 2 mcg/kg (usually 0.5-1 mcg/kg)

Question 24

What is the infusion dose of Fentanyl?

Answer 24

0.01 - 0.05 mcg/kg/min

Question 25

What is the GA IV dose for a sole agent, for Fentanyl?

Answer 25

50 - 150 mcg/kg

Question 26

What is the regional anesthesia dose for Fentanyl?

Answer 26

Epidural: 50 - 100 mcg (loading)
Spinal: 10 - 25 mcg

Question 27

What is the reversal/ antagonist of Fentanyl and the dose of it?

Answer 27

Naloxone (Narcan) at 0.1 - 2 mg IV incremental doses; 10 mg max

Question 28

Is Fentanyl more or less lipid soluble than morphine with a longer or shorter DOA?

Answer 28

MORE lipid soluble than Morphine with SHORTER DOA- 75% of initial dose undergoing first pass pulmonary uptake

Question 29

_______ redistribution to _________ tissue sites as ______, _________ _________, and ________

Answer 29

rapid redistribution to inactive tissue sites as fat, skeletal muscle, and lungs

Question 30

What can multiple IV doses or continuous infusion produce?

Answer 30

progressive saturation of inactive tissue->leads to 2nd peak b/c comes back to plasma

Question 31

Does plasma concentration decrease rapidly?

Answer 31

Plasma concentration does NOT decrease rapidly and DOA is prolonged-> 2dary peak in plasma levels

Question 32

What is the clinical significance of Fentanyl?

Answer 32

• Used as analgesic adjunct for surgery
• as adjuvant to blunt stimulation of incision, laryngoscopy
• as sole anesthetic in large doses due to hemodynamic stability
• 100 x more potent than morphine
• wide range of doses given: 1-20 mcg/kg
• Lozenges (fent lollipop) 5-20 mcg/kg 45 min prior to induction