Remifentanil

Question 1

What is the brand/trade name for remifentanil?

Answer 1

• Ultiva

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

UpToDate - Remifentanil: Drug Information

Question 2

What is the pharmacologic category/class of remifentanil?

Answer 2

• Opioid Analgesic — Synthetic
• Phenylpiperidine

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

UpToDate - Remifentanil: Drug Information

Question 3

What is the mechanism of action of remifentanil?

Answer 3

Selective mu opioid rececptor agonism, 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

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

Stoelting’s Pharmacology (5th ed.), pp. 218-219, 237

Question 4

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

Answer 4

• 0.5-1 mcg/kg IV over 60-90 seconds

This helps to blunt the SNS response

Other sources say up to as much as 3 mcg/kg

Nagelhout (7th ed.), p. 145 - Table 11.5

Stoelting’s Pharmacology (5th ed.), p. 238

UpToDate - Remifentanil: Drug Information

Question 5

Remifentanil can administered as a continous infusion as the analgesic component of a general anesthetic or during procedural sedation - what is the dosing range for this indication?

Answer 5

• 0.05-2 mcg/kg/min IV

lower end for sedation/MAC cases, higher end for GA

Stoelting’s Pharmacology (5th ed.), pp. 238-239

UpToDate - Remifentanil: Drug Information

Question 6

What is the onset of action for remifentanil?

Answer 6

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

Nagelhout (7th ed.), p. 146 - Table 11.6

UpToDate - Remifentanil: Drug Information

Question 7

What is the duration of action for remifentanil?

Answer 7

• ~10 minutes

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

Nagelhout (7th ed.), pp. 141, 146 - Table 11.6, 148

UpToDate - Remifentanil: Drug Information

Question 8

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

Answer 8

• Metabolism: hydrolysis by blood/plasma esterases
  _{not influenced by quantitative/qualitative changes in pseudocholinesterase}
• Elimination: Kidneys

Half-life: ~10 minutes

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

Nagelhout (7th ed.), pp. 146 - Table 11.6, 148

UpToDate - Remifentanil: Drug Information

Question 9

Cardiovascular effects of remifenanil include:

Answer 9

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

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

Nagelhout (7th ed.), pp. 143

Question 10

What are the respiratory effects of remifentanil?

Answer 10

• 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.), pp. 222, 237

Question 11

What are the effects of remifentanil on the CNS?

Answer 11

• 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. 223

Question 12

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

Answer 12

• 1 mg powder for reconstitution

UpToDate - Remifentanil: Drug Information

Question 13

Rapid IV administration of large doses of remifentanil can lead to generalized ______________; the greatest impact is on the ability to ______________

Answer 13

• 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 14

What are the GI/GU effects of remifentanil?

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}

Maybe not as much as others?

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

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

Answer 15

Along with other opioids, remifentanil effects

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

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

Question 16

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

Answer 16

• ~100

equivalent to fentanyl

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 17

Identify which of the following represents the context sensitive half-time of remifentanil

Answer 17

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 8. Remifentanil

Question 18

Explain the rationale behind why remifentanil is not used in neuraxial anesthesia?

Answer 18

It includes glycine as a buffer:

• Glycine is an inhibitory neurotransmitter and there is potential for skeletal muscle weakness or neurotoxicity

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 8. Remifentanil

Nagelhout (7th ed.), p. 148

Question 19

Remifentanil can cause acute opioid-induced ___________ following discontinuation

Answer 19

• hyperalgesia

NMDA receptor antagonists (ketamine, magnesium) may be useful in preventing/managing this

Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 8. Remifentanil

Stoelting’s Pharmacology (5th ed.), p. 239