Opioid and non-opioid analgesics 4 Flashcards
Which are expected to increase during an episode of opioid-induced muscle rigidity? (select 3)
a. oxygen consumption
b. thoracic compliance
c. pulmonary vascular resistance
d. intracranial pressure
e. functional residual capacity
f. mixed venous oxygen saturation
a. oxygen consumption
c. pulmonary vascular resistance
d. intracranial pressure
Rapid IV administration of opioids can cause
skeletal muscle rigidity
Skeletal muscle rigidity from opioids is more common with
liphophilic compounds such as sufentanil, fentanyl, remifentanil, and alfentanil
The best treatment for opioid-induced skeletal muscle rigidity is
paralysis and intubation
Historically, skeletal muscle rigidity has been described as ____________ however current evidence suggests that the greatest resistance to ventilation occurs in the
chest wall rigidity or stiff chest syndrome; larynx
Opioid-induced muscle rigidity is believed to result from
mu receptor stimulation in the CNS (ultimately influencing dopamine and GABA motor pathways)
Can naloxone be used to reverse rigidity?
yes but it would be counterproductive for surgery
What are the CV complications of opioid-induced muscle rigidity?
increased CVP, increased PAP, increased PVR
What happens to ICP and gastric pressure with opioid-induced muscle rigidity?
both increased
What happens to the respiratory system with opioid-induced muscle rigidity?
hypoxia
hypercapnia
increased oxygen consumption
decreased SvO2, thoracic compliance, FRC, and minute ventilation
What 4 opioids are most likely to cause skeletal muscle rigidity?
sufentanil
fentanyl
remifentanil
alfentanil
Opioid partial agonists can never
achieve the same intensity of effect at a specific receptor as a full agonist
Partial opioid agonists produce
analgesia with a reduced risk of respiratory depression
Partial opioid agonists have a ___________ beyond which additional analgesia is not possible.
ceiling effect
Examples of partial opioid agonists include
buprenorphine, nalbuphine, and butorphanol
Partial opioid agonists reduce the
efficacy of previously administered opioids
Can partial opioid agonists cause acute opioid withdrawal?
yes, they can do so in the opioid-dependent patient
Partial opioid agonists _________ dependence
carry a low risk of
What is the MOA of buprenorphine?
Mu agonist (partial)
What is the analgesic effect of buprenorphine compared to morphine?
greater
Can buprenorphine be reversed by naloxone?
difficult d/t high affinity for mu receptor
What are key features of buprenorphine?
long duration (8 hours)
available via transdermal route
What is the mechanism of action of nalbuphine?
kappa agonist
mu antagonist
What are the analgesic effects of nalbuphine compared to morphine?
similar
Can nalbuphine be reversed by narcan?
yes
What are the key features of nalbuphine?
does not increased BP, PAP, HR, or RAP
useful with h/o heart disease
What is the mechanism of butorphanol?
kappa agonist
mu antagonist (weak)
What is the analgesic effect of butorphanol compared to morphine?
greater
Can butorphanol be reversed by naloxone?
yes
What are key features of butorphanol?
useful for postop shivering
available via intranasal route
What are 4 disadvantages of using partial agonist opioids?
- reduces the efficacy of previously administered opioids
- can cause acute opioid withdrawal in the opioid-dependent patient
- can cause dysphoric reactions
- has a ceiling effect beyond which additional analgesia is not possible
An opioid-dependent patient is scheduled for a cesarean section. Side effects of naloxone administration in this patient include all of the following EXCEPT:
a. pulmonary edema
b. bradycardia
c. nausea
d. neonatal withdrawal syndrome
b. bradycardia
Naloxone competitively antagonizes
mu, kappa, and delta receptors
Naloxone has the greatest affinity at the
mu receptor
The dose of naloxone is _______
1-4 mcg/k
Naloxone duration of action is
30-45 minutes
If a long acting opioid is the cause of respiratory depression, then a
narcan infusion should be considered
This drug is useful for mitigating the peripheral effects of opioids such as opioid-induced bowel dysfunction
methylnaltrexone- doesn’t cross the BBB
In the patient with pain, analgesic reversal activates
the SNS
Activation of the SNS with narcan can lead to
neurogenic pulmonary edema, tachycardia, cardiac dysrhythmias, and sudden death
What are the indications for using naloxone?
acute reversal of opioid-induced respiratory depression
treatment of opioid overdose
reversal of respiratory depression in the neonate whose mother received an opioid
How is naloxone metabolized?
liver (significant first-pass metabolism)
_____________ minimizes the effects of naloxone activating the SNS
slow titration
Does naloxone cross the placenta?
yes- if given to an opioid abusing mother it can precipitate acute opioid withdrawal in the neonate
Other side effects of naloxone include
nausea & vomiting- slow titrating can lessen
Naloxone infusion can relieve____________ in a patient receiving neuraxial opioids
severe pruritus
