Pharm Ch 10 basics Flashcards
actue pain
sudden, last less than 6 weeks
agonist
a substance that binds to a receptor and causes a response
nociceptors
sensory nerve fibers that result in pain
most important receptors in pain
mu - in dorsal horn of spinal cord, then kappa and delta
less mu receptors =
more pain, and vice versa
pain threshold is…
physiological
pain tolerence is…
psychological
visceral and superficial pain usually requires..
opioids
somatic pain usually requires (bone pain)
NSAIDS
vascular pain (you know this so well)
headaches
central pain
tumors, trauma, inflammation, disease (cancer, diabetes, stroke, MS)
nociception
gate permits action potentials from spine to cerebral cortex and you feel pain
gate theory
tissue injured - substances like bradykinin, histamine, potassium, prostaglandins and seratonin released.
then action potential at distal end of sensory nerve fibers. they go to dorsal horn where gates are located.
gate is activated by
large A fibers and small C fibers
A fibers…
close the gate
C fibers…
open the gate
A and C allow
the brain to evaluate, indentify and localize the pain. Then it closes or opens the gate.
sharp and localized pain - A or C?
A
dull and non-localized - A or C?
C
the body’s painkillers
enkephalins and endorphins
1 in 3 americans
ongoing pain
PCA
morphine pump
PCA by proxy
killed family w/ morphine pump
tolerence can occur in little as a
week
drugs added to opioid regime
NSAIDs, antidepressants, antiepileptic and corticosteroids (this is synergy)
allodynia
bed sheets hurt w/ neuropathy
3-step analgesic ladder
step 1 - nonopioids
step 2 - opioids
step 3 - opioids w/ or or without nonopioids or adjuvant meds
opioids are classified as
both mild agonists and strong agonists
strong trend away from (route)
intramuscular injections
opioids can be classified by their…
chemical structure or their mechanism of action
chemical structure is…
morphine-like, meperidine-like, and methadone-like
opioid mechanism of action
angonist, agonist-antoagnist, or antogonist
equianalgesia
hydromorphone (dilaudid) 7 times more potent than morphine
opioid tolerant
a week or longer - 60 mg morphine daily, oral oxy 30 mg daily, minimum of 8 mg oral hydromorphone daily, or any other opioid equivalent.
immediate release opioids usually last about
4 hours
contraindications to opioids
known allergies and severe asthma
codeine comes from
opium - natural opiate
codeine is only agonist with
ceiling effect (increasing dose will not increase response)
