Alfentanil Flashcards
What is the brand/trade name for alfentanil?
What is the pharmacologic category/class of alfentanil?
- Opioid Analgesic — Synthetic
- Phenylpiperidine
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 4. Classification, Relative Potency & Opioid Abuse
*Nagelhout (7th ed.), p. 139 - Box 11.1
What is the mechanism of action of alfentanil?
Opioid rececptor agonism, especially mu, with resultant increase in pain threshold, altered pain perception, and inhibition of 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
When used as an adjunct during induction and intubation what is the dosing range for alfentanil?
- 5-150 mcg/kg IV
This helps to blunt the SNS response
Dose varies based on the anticipated length of the procedure
Nagelhout (7th ed.), p. 145 - Table 11.5
Stoelting’s Pharmacology (5th ed.), p. 237
What is the onset of action for alfentanil?
- Rapid/Immediate
Fastest of all the opioids
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 7. Alfentanil
Nagelhout (7th ed.), p. 146 - Table 11.6
Stoelting’s Pharmacology (5th ed.), p. 236
What is the duration of action for alfentanil?
- ~15-30 minutes, but varies depending on dose
Shorter than fentanyl
Half-life: ~1.5 hrs
Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1
Nagelhout (7th ed.), pp. 146 - Table 11.6, 147
Stoelting’s Pharmacology (5th ed.), pp. 236-237
What organ(s) are responsible for alfentanil’s clearance (metabolism/elimination)?
- Metabolism: Liver (P450)
- Elimination: Kidneys
No active metabolites, but susceptible to prolonged effects due to interactions/alterations in CYP3A4 function
Anesthesia Guidebook - Episode 17: Anesthesia Top Drawer Run Down - Part 1
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lesson 7. Alfentanil
Nagelhout (7th ed.), p. 147
Stoelting’s Pharmacology (5th ed.), p. 236
Cardiovascular effects of alfentanil include:
- Bradycardia
- Stable SVR/MAP
no histamine release
More likely to improve BP after increases related to painful stimulation
Apex Unit 5: Pharmacology 2; Opioid & Non-Opioid Analgesics; Lessons 2 & 3
Stoelting’s Pharmacology (5th ed.), p. 237
What are the respiratory effects of alfentanil?
- 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
What are the effects of alfentanil on the CNS?
- Sedation
- Miosis/pinpoint pupils
- Mild hypothermia
resets hypothalamic temperature setpoint - N/V (less than fentanyl/sufentanil)
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.), pp. 223, 237
What is the concentration (mcg/mL) of alfentanil vials?
- 500 mcg/mL
Duh, just remember it’s 10x less potent than fentanyl
Vials are often 2 mL, or 5 mL
Rapid IV administration of large doses of alfentanil 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 alfentanil?
- Slowed peristalsis → CONSTIPATION
- N/V
(less than fentanyl/sufentanil) - Contraction of sphincter of Oddi → biliary colic
evidence is kind meh on this - Delayed gastric emptying
- Urinary retention (IDGAF)
detrusor relaxation, urinary sphincter constriction
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, 237
The experience of pain can be divided into four steps: transduction, transmission, modulation, and perception. Which of these does alfentanil 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, alfentanil is __________ times more potent than morphine and _________ times LESS potent than fentanyl
- ~10
- ~10
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
Stoelting’s Pharmacology (5th ed.), p. 236
