Opioids Flashcards
opioids are classified into (3)
full agonists
partial agonists
antagonists
major target receptor for opioids
μ - mu
moa for opioids
mimic endogenous opioid peptides
where are endogenous opioid peptides found
regions associated w. pain transmission →
spinal cord
limbic system
3 endogenous opioid peptides
enkephalins
endorphins
dynorphins
enkephalins are found in the (2)
brain
adrenal medulla
endorphins are found in the (2)
brain
pituitary gland
t/f: opioid peptides can elicit all responses associated w. opioid drugs, including tolerance and dependence
T!
opioid analgesics interact w. __ opioid receptors (2)
to produce __ effects (2)
peripheral and CNS
therapeutic and adverse
primary moa of opioids
decreased NT release → decreased neuronal excitability
decreased NT release of opioids is __ linked
G protein
Mu (morphine receptor) mediates
spinal/supraspinal analgesia
respiratory dpn
reduced GI motility
miosis
euphoria
physical dependence
kappa (dynorphin) receptors mediate
spinal analgesia
miosis
sedation
dysphoria
delta (enkehalin) receptors mediate
similar to mu
subjective experience of pain =
perception + rxn
inhibitory effects of opioid action are associated with the __ pathway
descending
inhibitory effects of opioids include (3)
change in rxn to pain
increase in pain threshold
spinal analgesia
sensitization to pain and transduction of pain stimuli are associated w.
COX 2 → PG
perception of, and rxn to, pain is associated w. the __ pathway
ascending →
spinothalamic tract
limbic system
cortices
analgesic effect of elevation of pain threshold occurs at the
somatosensory cortex → activation of brain stem (descending inhibition)
presynaptic elevation of pain threshold occurs via decrease of __ from spinal cord neurons (2)
substance P
glutamate
postsynaptic decrease of pain threshold occurs via decreased response of __ neurons
2nd order pain transmission
change in subjective response to pain occurs in the __
via inducement of __ (2)
limbic system
tranquility/euphoria
opioid drugs are more efficacious but also more dangerous for relief of __ pain
mod-severe
analgesic effects of opioids are __,
whereas analgesic effects of NSAIDs exhibit a __
dose-dependent
ceiling effect
are opioids antipyretic or anti-inflammatory
no!
3 non analgesic uses of opioids
cough suppression
anti-diarrheal
MI
which opioid is used as a cough suppressant
dextromorphan
why is dextromorphan lower risk for abuse potential
lower doses required for cough suppression
which opioid is used as a anti-diarrheal agent
loperamide
why is loperamide low risk for parenteral abuse
low-solubility salts
which opioid is used for pain/anxiety relief for MI
fentanyl
does fentanyl have any effect on myocardial fxn
not really
opioids are first line for __ pain,
but NOT for __ pain
acute mod-sev
chronic
what is included in opioid use disorder (7)
respiratory dpn
n/v
sedation
dizziness
constipation
dry mouth
pruritis
mc affective response to pain w. opioids
euphoria
why are we worried about euphoria w. chronic opioid use
produces changes in brain-reward pathway → opioid use disorder
what percentage of people on longterm opioids for non cancer pain in PCP setting struggle w. addition
25%
most serious acute s.e of opioid drugs if pt does not follow dosing guidelines
respiratory dpn
rarely a problem if dosing guidelines are followed
moa for respiratory dpn w. opioids
decrease in sensitivity of respiratory centers to CO2
risk for respiratory dpn increases when (3)
opioids titrated rapidly
sleep apnea
co-administered w. benzos
__ precedes
__ w. respiratory dpn related to opioids
prominent sedation
significant dpn
how many ppl die daily from prescription opioid od’s
40+
classic triad of opioid od
coma
pinpoint pupils
respiratory dpn
tx for opioid od if somnolent but easily arousable
NO naloxone!
when do you administer naloxone for opioid od
symptomatic respiratory dpn
OR
progressive obtundation (alterness/consciousness)
decreased RR is imminent
t/f: duration of naloxone is shorter than agonists
T!
what might occur in addicts who are given naloxone
withdrawal sx →
sweating, increased RR, agitation
constipation caused by opioids is both __ (2)
direct
indirect
direct reduction of bowel motility w. opioids is mediated via
mu receptors → inhibit ENS fxn
indirect reduction in bowel motility of opioids is caused by
decrease in Ach release → anticholinergic effect
t/f: do pt’s on opioids develop tolerance to constipation
no!
constipation worsens as dose increases
pt’s on opioids must be given prophylactic pharm for
constipation
common first line prophylactic pharm for constipation dt opioids
daily senna (stool softener)
+/- docusate
is docusate effective alone for constipation
nope!
other tx to try for opioid constipation (besides senna)
PEG-sorbitol daily or PRN
bisacodyl enema
list drugs in order of effectiveness for prophylaxis of constipation
trick question!
they are equally effective