Chapter 31 - Opioids Flashcards
What chemical mediators are released with tissue injury?
-bradykinin
-histamine
-substance P
-prostaglandins
-serotonin
-leukotrienes
Opiod
any drug, natural or synthetic, that has actions similar to morphin
Opiate
term that applies only to compounds present in opium
Which 3 peptide families have opioid-like properties?
-enkephalins
-endorphins
-dynorphins
What are Mu opioid receptors?
receptors that are the MOST important for opioids - involve analgesia, respiratory depression, euphoria, sedation, physical dependence
What are kappa opioid receptors used for?
analgesia and sedation
What receptor is responsible for underlying psychomimetic effects?
kappa receptors
Which receptor type does not interact with opioids?
delta
What receptors do pure opioid agonists interact with?
Mu and kappa
What effects do pure opioid agonists produce?
-analgesia
-euphoria
-sedation
-respiratory depression
-physical dependence
-constipations
What drugs are pure opioid agonists?
morphine and codeine
What drugs are agonist-antagonist opioids?
-pentazocine
-nalbuphine
-butorphanol
-buprenorphine
What effect do agonist-antagonist opiods have when administered alone?
analgesia
What do agonist-antagonist opiods do with pure agonists?
antagonize analgesia
All opiods are measures against what drug??
morphine
How does morphine act?
mimics actions of endogenous opioid peptides primarily at Mu receptors
What are the adverse effects of morphine?
-**respiratory depression
-constipation
-urinary retention
-drowsiness
-orthostatic hypothension
-emesis
-miosis
-cough suppression
-tolerance and dependence
-brain fog
WHAT IS A MAJOR COMPLICATION OF OPIOIDS?
RESPIRATORY ARREST
Who is most susceptible to resp. depression from morphine?
infants and elderly
What is the onset of IV morphine?
7 mins
What is the onset of IM morphine?
30 min
What is the onset of subQ morphine?
up to 90 mins
How long does morphine last?
4-5 hrs
Spinal morphine injection may be ______________
delayed
What contributes to constipation from morphine?
-suppressed propulsive contractions
-intensified non-propulsive contractions
-increased anal sphincter tone
-inhibited secretion of fluids into lumen
What is the tx for morphine induced constipation?
-activity
-fibre and fluid intake
-stimulant laxatives
-stool softeners
-polyethylene glycol
How does morphine cause orthostatic hypotension?
blunts baroreceptor reflex by causing vasodilation
How does morphine cause urinary retention?
-increase tone in bladder sphincter
-increased tone in detrusor muscle
-suppresses awareness of bladder stimuli
How does morphine suppress cough?
-acts on receptors in medulla to suppress reflex
-secretions accumulate in airway
What does patient teaching about coughing post-morphine occur?
cough reflex is suppressed, secretions must be cleared at regular intervals
How does morphine produce emesis?
-direct stimulation of chemoreceptors in medulla
-rxn. greatest with initial dose
-more common in recumbent patients
How does morphine elevate ICP?
-reduced respirations increases CO2 in blood that dilates cerebral vasculature
Euphoria
exaggerated sense of well-being caused by Mu receptor activation
Dysphoria
sense of anxiety and unease
When does dysphoria occur?
when morphine is taken in the absence of pain
How do you avoid sedation with morphine?
-smaller doses more often
-use opioids with short half-lives
Miosis
pupillary constriction
How do pupils appear with morphine toxicity?
pinpoint pupils
What are risk factors for neurotoxicity caused by morphine?
-renal impairment
-pre-existing cognitive impairment
-prolonged opioid use
How is neurotoxicity managed with morphine use?
hydration and dose reduction
Is morphine lipid soluble?
not really, doesn’t cross BBB easily
What AEs does morphine tolerance develop to?
-analgesia
-euphoria
-sedation
-respiratory depression
-NOT CONSTIPATION OR MIOSIS
What are the initial morphine withdrawal symptoms that start 10hrs after the last dose?
-yawning
-rhinorrhea
-sweating
What are the subsequent symptoms of morphine withdrawal?
-violent sneezing
-weakness
-nausea
-vomiting
-diarrhea
-abdominal cramps
-bone and muscle pain
-muscle spasms
-kicking movements
How long does morphine withdrawal last if untreated?
7-10 days
What is the classic triad of morphine TOXICITY?
-coma
-respiratory depression
-pinpoint pupils
What is the treatment for morphine toxicity?
ventilation support and NALOXONE (narcan)
2 guidelines for morphine?
-monitor vitals
-give on fixed schedule
How many times more potent is fentanyl than morphine?
80-100x
___% of codeine is converted to morphine via CYP2D6
10
What strength are codeine, oxycodone, and hydrocodone?
moderate to strong opioid agonists
What kind of opioid is Buprenorphine?
an agonist-antagonist opioid
How is buprenorphine administered?
-7 day patch
-SL tabs
Why is Buprenorphine used over other drugs?
substance use replacement therapy because it works differently
How does buprenorphine act?
as a partial agonist at Mu receptors and antagonist at kappa receptors
What effect does buprenorphine provide?
analgesic effects (like morphine) with less respiratory depression
What is an adverse effect of buprenorphine?
prolonged QT interval
When are opioid antagonists used?
-treatment of OD
-constipation relief
-reversal of post-op effects
-reversing neonatal respiratory depression
-addiction management
What is naloxone (narcan)?
a reversal agent for opioids
What receptors does naloxone work at?
Mu and Kappa
What opioid antagonist is used more often to treat addiction?
naltrexone - prevents euphoria if user takes an opioid
What is methylnaltrexone (antagonist) used to treat?
opioid-induced constipation
How do non-opioid centrally acting analgesics act?
relieve pain in a way unrelated to opioid receptors
Do non-opioid analgesics have the same risks?
no respiratory depression or abuse
What are the 2 non-opioid analgesics?
tramadol and tramacet (tramadol and acetaminophen)
What receptors do tramadol and tramacet work at?
NE and 5-HT (serotonin)
Tramadol and tramacet are ___________ analogues
codeine
What are the side effects of tramadol and tramacet?
-sedation
-dizziness
-headache
-dry mouth
-constipation
When should tramadol and tramacet not be used?
high suicide risk pts
