Remifentanil Flashcards
What is the brand/trade name for remifentanil?
What is the pharmacologic category/class of remifentanil?
- Opioid Analgesic — Synthetic
- Phenylpiperidine
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 4. Classification, Relative Potency & Opioid Abuse
What is the mechanism of action of remifentanil?
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
When used as an adjunct during induction and intubation what dose of remifentanil is used?
- 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
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?
- 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
What is the onset of action for remifentanil?
- “Rapid/immediate” with maximal effects in 2-5 minutes
Nagelhout (7th ed.), p. 146 - Table 11.6
What is the duration of action for remifentanil?
- ~10 minutes
Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1
Nagelhout (7th ed.), pp. 141, 146 - Table 11.6, 148
What organ(s) are responsible for remifentanil’s clearance (metabolism/elimination)?
- 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
Cardiovascular effects of remifenanil include:
- Bradycardia
- Stable SVR/MAP
no histamine release
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 2 & 3
Nagelhout (7th ed.), pp. 143
What are the respiratory effects of remifentanil?
- 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
What are the effects of remifentanil on the CNS?
- 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
What is the concentration (mg/mL) of remifentanil vials?
- 1 mg powder for reconstitution
Rapid IV administration of large doses of remifentanil can lead to generalized ______________; the greatest impact is on the ability to ______________
- 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
What are the GI/GU effects of remifentanil?
- 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
The experience of pain can be divided into four steps: transduction, transmission, modulation, and perception. Which of these does remifentanil have an effect on?
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
As an analgesic, remifentanil is __________ times more potent than morphine
- ~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
Identify which of the following represents the context sensitive half-time of remifentanil
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 8. Remifentanil
Explain the rationale behind why remifentanil is not used in neuraxial anesthesia?
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
Remifentanil can cause acute opioid-induced ___________ following discontinuation
- 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
