NEURO - Opioids Flashcards
(28 cards)
List of opioid analgesics
Morphine Fentanyl codeine Loperamide diphenoxylate methadone meperidine dextromethorphan pentazocin nalbuphine Buprenorphine
Mechanism of tolerance of opioids
NMDA phosphorylation of opioid receptors via glutmate
*decrease this tolerance with glutamate antagonism i.e. ketamine
mu ligand
beta-endorphin (form POM-C)
kappa ligand
dyorphin
delta ligand
enkephalin
MOA of opioid analgesits
open K+ channels
Close Ca++ channels
.: Decreases synaptic transmission
Inhibits release of ACh, NE, 5-HT, glutamate, substance P
Opioid for cough
dextromethorphan
opioids for diarrhea
loperamide
diphenoxylate
(don’t cross BBB)
opioids for heroin addicts
methadone Suboxone Naloxone Naltrexone Methylnaltrexone
opioid analgesic that causes inhibition of muscarinic receptors
meperidine
.: classic s/s of opioid intoxication are REVERSED! i.e. dilated pupils
Opioid analgesics that can cause serotonin syndrome
meperidine (via normeperidine metabolite)
Dextromethorphan
Mixed agonist-antagonists
Nalbuphine
Pentazocin
kappa agonist
mu antagonist
Methadone
methadone (long-acting agonist)
Suboxone
(buprenorphine = partial agonist, SL; + naloxone = antagonist, IV)
Naloxone
(antagonist; acute OD)
Naltrexone
(antagonist; long t1/2, decrease alcohol and heroin cravings)
Mehtynaltrexone
Treats opioid-induced constipation: antagonist that can’t cross BBB, so doesn’t induce withdrawal
General use of opioids
Pain, acute pulmonary oedema
Tolerance does NOT develop to:
miosis and constipation
Opioids and head trauma
contraindicated; cause vasodilation and histamine release
Opioids and smooth muscle effects
Longitudinal relaxation, but circular constriction: - cramps, constipation, decreased peristalsis - urinary retention - sphincter of oddi constriction - miosis
Butorphanol
kappa agonist and mu partial agonist
agonist-partial agonist
Butorphanol - kappa agonist and mu partial agonist
Butorphanol use
severe pain i.e. labour, migraine
Causes less respiratory depression
