Opoids Flashcards
1. List the three opioid receptor subtypes, the endogenous ligands for each receptor subtype, and the prototype exogenous opioid agonists that bind to each receptor subtype 2. List at least 8 important pharmacological effects produced by opioid agonists and name the receptor subtype that mediates each effect 3. Describe the differences in the pharmacology between full and partial opioid agonists 4. List the prototype opioid receptor antagonists, list which receptor subtype they bind to,
three opioid receptor subtypes
Mu, Delta, Kappa
role of Mu receptor
supraspinal analgesia, miosis, respiratory depression, euphoria, dependance
role of kappa receptor
spinal analgesia, sedation
opioid receptor type
G protein
endogenous opioid that has affinity to mu
Beta
endogenous opioid that has affinity to delta
enkephalin
endogenous opioid that has affinity to kappa
dynorphins
path of pain sensation
peripheral stimulation creates APs –> APs travel up nerve to dorsal horn of SC –> up 2nd nerve to thalmus/brainstem –> 3rd nerve to cortex for pereption
where opiods work
spinal and supraspinal levels
opioid MOA in presynaptic terminal
decreases Ca++ influx in response to incoming APs - keeps neuron bouton from releasing NT
NT in pain circiut
substance P
opioid MOA in postsynaptic terminal
increases K+ conductance and thereby decreases the postsynaptic response to exitatory neurotransmission
analgesic effects of opioids
effective against dull pain
decreases response to pain
increases pain threshold
GI theraputic effects of opioids
increased tone and decreased motility
antitusive MOA of opioids
suppression of cough reflex in medullary center
adverse effects of opioids
respiratory depression, miosis, sedation, euphoria, emesis, urinary retention, bilary spasm, chest wall rigidity
effects of opioids that tolerance occurs to
deppressent effects
timimg of opioid withdrawal
begins 6 hrs after last dose, peaks at 48 hours, declines for 10 days
sx of opioid withdrawal
sweating, nausea, vomiting, cramps, shivering, shakes, restlessness,
most active forms of opioids
levo forms
example mu-agonists (9)
morphine, heroin, codine, meperidine, fentanyl, congeners, methadone, propoxyphene, pentazocine, buprenorphine, tramadol
reason heroin is more abused
higher potency, higher lipid soluability
protoype mu agonist
morphine
used as antitussive
codine
mu agonist with anticholenergic effects
meperidine
OD of this can lead to convulsions
meperidine
opioids used as anesthetic adjuvants
fentanyl/ xxxx-entanil
opioid that uses the dextro form
propoxyphene (darvocet)
popular opioid for mild to moderate pain
propoxyphene
partial mu agonist
pentazocine/buprenorphine
alternative to methadone
buprenorphine
use of tramadol
restless leg, fibromyalgia, acid reflux, premature ejacualtion
MOA of tramadol
weak partial mu agonist, blocks NE reuptake, releases serotonin
opioids that are metabolized to active compounds
morphine, meperidine, heroin, hydrocodone, oxycodone
opioid antagonists
naloxone, naltrexone,
short acting opioid antagonist
naloxone
long acting opioid antagonist
naltrexone
opioid antagonist used in maintaince therapy
naltrexone
opioid antagonist used in emergency
naloxone
anti-tussive that does NOT work on opiod receptors
dextromethorphan
opioids used at anti-diarreha
loperamide and diphenoxylate
widely abused prescription opioid
oxycodone
