opioids Flashcards
analgesics
drugs that relieve pain WITHOUT loss of conciousness
opioid
a drug that has actions similar to morphine
endogenous opioid peptides
have opioid- like properties
found in cns and peripheral tissue
3 main receptors
mu
kappa
delta
most important opioid receptor to opioids.
MU
Mu receptor response to activation
Analgesia
Euphoria
Respiratory Depression\
related to physical dependence
Kappa receptors response to activation
analgesia and sedation
three groups of opioids
1) pure opiod agonists
2) agonist-antagonist opiods
3) pure opiod antagonists
pure opioid agonists
produce similar response to endogenous opioids
- analgesic euphoria
- sedation
-physical dependence
- respiratory depression
2 groups of pure opioid agonists
1) strong opioid agonist (morphine)
2) moderate to strong opioid agonists
agonist-antagonists opioids
administered alone = low level analgesia
administered with pure agonist = blocks pure agonists
- decrease analgesia
pure opioid antagonists
acts as antagonists on mu and kappa receptors
- stops receptor from activating a response
REVERSAL of resp. and CNS depression caused by opioid agonist overdose
common opioid antagonists
NALOXONE
Pure agonists
Morphine
morphine pharmalogic effects
analgesia
sedation
euphoria
resp depression
cough suppression
morphine source
poppy plant
extract from opium
contains codeine (analgesic)
and papaverine (smooth muscle relaxant)
Pharmacological Actions
analgesic
sense of well-being
reduces anxiety
mental clouding
- respiratory depression, urinary retention
- prolongued use = physical tolerance and physical dependence
Morphine Therapeutic Uses
relief of moderate to serve pain without unconsciousness
Mechanism of Analgesic action
mimics endogenous opiods at mu
morphine adverse effects
Resp depression: ++ cause of overdose death
may last 4-5 hrs
Chronic use = resp tolerance occurs
Constipation- by activating me receptors in gut
Orthostatic hypotension
- blunts barocrecptor reflex and dilate arterioles and veins
Urinary retention
- increase tone sphincter and detrusor muscle
Cough Supression
- -acts on opioid receptors in medulla
When should morphone not be used?
if resp rate is less than 12 breaths per minute
How do you reverse morphine overdose
Naloxone
Morphine pharmocokinetics
poor lipid solubility
cant cross BBB easily
- only a fraction reaches analgesic recptors
PO= ++ inactivated First Pass
Tolerance= analgesia, euphoria, sedation, resp depression
Physical dependence of morphine
abstinence syndrome occurs when drug stopped
due to cellular changes
- once changes occur, body needs constant opioids to function normally
How long do opioid withdrawals last?
management?
Exterme but not LETHAL
- begins 5 hours after final dose/ lasts 7-10 days
withdrawal gradually
- progressively smaller doses over 3 days
Morphine Toxicity
classic triad
-coma
- resp. depression
- pinpoint pupils
treatment for opioid toxicity
ventilatory support
opioid antagonist
fentanyl
transdermal
- drug placed on skin and is absorbed into blood stream
trans mucosal: intranasal, buccal, rectal, sublingual
bucal: between gums and cheek
Methadone
used to treat opioid addiction
methadone adverse effects
prolongs QT interval= potentially fatal dysthmia’s
strong opioid agonists
morphine (prototype)
fentanyl
methadone (treats opioid addiction)
moderate to strong opioid agonists
less anglgesia, resp depression, lower potential for abuse
Codeine
Codeine
For mild- moderate pain
10% converted to morphine in liver
cough suppressant
Pure antagonist function and therapeutic uses
Block effects of opioid agonists
treat opioid OVERDOSES
relief opioid induced CONSTIPATION
Reversal POSTOPERATIVE opioid effects
Mgmt opioid ADDICTION
Naloxone mechanism
reverses effects of opioid agonists
how is Naloxone administered and elimiated?
IV
IM
Intranasally
SubQ
Elimination: liver
Naloxone therapeutic uses
reversal of opioid overdose
initiate with a series of small doses until crisis has passed
reversal neonatal resp depression during birth
Opioid antagonist
Narcan
Methylnaltrexone Naloxegol Naldemedine
Naltrexone
Methylnaltrexone Naloxegol Naldemidine
selective mu receptor antagonists
opiod-induced constaptation relief–> try other measures first
work in periphery
- Do not block CNS
Naltrexone
PO, IM
opioid abuse- prevent euphoria
alcohol abuse- prevent buzz
Non- Opioid centrally acting analgesics
Tramadol
Tramadol
moderately stong analgesic
low potential for dependence/ resp depression
tramadol mechanism of action
weak action of mu receptors
- works primarily by blockinh uptake of norepinephrine and serotonin
–> inhibitory effects on pain transmission in spinal cord
less effective than morphine
more effective than codeine
