opiods Flashcards
Full opioid agonists
morphine
fentanyl
heroin
methadone
partial opioid agonists
codeine
hydrocodone
oxycodone
mixed agonists/antagonists
buprenorphine
antagonisits
naloxone
weak opioid agonists/reuptake inhibitors
tramadol
tapentadol
tramadol
serotonin uptake blocker
NE uptake blockers
weak mu-R agonist
tapentadol
weak muR agonist and NE reuptake blocker
narcotic
archaic term
more legal then medical referring to any substance that produces stupor associated with analgesia
opiates
natural products and derivatives obtained from opium poppy
- opium
- morphine
- heroine
- codeine
opiods
class of compounds that bind to opioid R includes agonists, antagonists, partial agonists, and mixed agonists/antagonists
endogenous opioid agonists
endorphin
enkephalines
dynorphins
muRs
endorpins>enkepalins>dynorphins supraspinal and spinal analgesia sedation inhibition of respiration slowed GI transit modulation of hormone and neurotransmitter release
kappa Rs
enkephalins>endorphins=dynorphins
supraspinal and spinal analgesia
modulation of hormone and neurotransmitter release
deltaRs
dynorphins>endorphins>enkephalins
other Rs
sigma
TLR-4
ORL-1
ORL-1
orphan opioid R like
cloned ‘orphan R’
similar structure to opioid R
different fnx (no effec on pain, hyperalgesia, or inflammation)
different ligands - nocipetin = orphanin FQ
opioid Rs
all GPCRs
inbitis cyclic AMP
open G-protien modulated KChS -> hyperpolarization
reduce presynaptic Ca influx inhibiting NT release
brain stem
opioid R influence respiration, cough, nausea, vomiting, BP, pupillary diameter, stomach secretion
medial thalamus
mediates deep pain that is poorly localized
spinal cord
receipt and integration of incoming sensory information, activation of these R attenuates painful afferent stimuli
hypothalamus
affect neuroendocrine secretion
limbic system
high density of opioid Rs in amygdala
periphery
peripheral sensory nn fibers and nn terminals inhibit Ca influx and release of excitatory and pro-inflammatory substances
immune cells
have opioid Rs, but fnx is unknown
major efects of activating mu
analgesia euphoria miosis respiratory depression physiological dependence reduced GI motility
major efects of activating kappa R
less abuse potential and physical dependence dysphoria psychotomimetic less miosis and respiratory depression then mu analgesia sedation vasodilation increased urinary output
miosis
d/t indirect parasympathetic actions
little or no tolerance develops against this
almost all other causes of coma cause mydriasis
opioids and CV system
no major effects on BP or heart rate
b/d of respiratory depression and CO2 retention cerebral vessels dilate -> increased ICP therefore use is CI in severe brain injury
opioids and Histamine
opioids release H2 from mast cells
CI in asthmatics
opioids and first pass
variable
morphine- very high
codeine and oxycodone less
opioids and pregnancy
do cross placental barrier therefore CI
fentayl PK
highly lipophilic slowly metabolized but short acting b/c distributes to fatty tissues 100x more potent then morphine IV, epidural, intrathecal
morphine
binds all opioid Rs highest affinity for mu low oral availability high efficacy for analgesia high abuse potential
uses of morphine
analgesic- best with severe, constant pain
acute pulmonary edema
acute MI
morphine and acute pulmonary edema
reduced perception of SOB
anxiolytic effects
reduction in cardiac preload and afterload
opioids and cough suppression
low doses
maybe d/t activation of sigma R
dextromethorphan
codeine
opioids and diarrhea
low doses
loperamide (cannot X BBB)
diephnoxylate (+atropine)
difenoxin (+atropine)
uses of fentanyl
epidural for labor
oral transumucosal and patch for CA pts
methadone
synthetic, PO effectice opioid
equally potent as morphine, but induces <euphoria with longer duration of action
analgesic
control withdrawl of heroin and morphine
meperidine
syntheitic opioid used for acute pain
binds both mu and kappa
respiratory depression
DILATES pupils
not useful for diarrhea or cough
less effects on smooth mm (can be used in obstetrics)
toxic metabolite causes seizures so cannot be used >48hrs
heroin
schedule I
3x more potent then morphine
greater lipid solubility so more CNS effects
more exaggerated euphoria
codeine
mu effects w/low doses
kappa effects w/high doses
hydrocodone
relatively pure mu actiavtion
oxycodone
relatively pure mu
derivative of codeine
high PO effects
sustained release product (oxycotin)
bupreoprhine
mixed opioid agonist/antagonists
depends on R subtype
partial agonist at mu
major use is for opioid detox
mixed opioid agonist/antagonists
can precipitate withdrawl symptoms
naloxone
opioid antagonist short acting used to Tx opioid overdose precipitates withdrawal syndrome can be used to Tx drug-fee addicts
primary symptoms of opioid overdose
triad:
lethargy/coma
depressed respiration
pinpoint pupils
secondary symptoms of opioid overdose
hypotension hypothermia w/cold or clammy skin pulmonary edema convulsions hypoxia w/dilated pupils
