Opioids Module Flashcards
MOA of Codeine
potency
- full MOR agonist
0. 01
MOA of Morphine
potency
- full MOR agonist
1
MOA of Hydrocodone
potency
- full MOR agonist
1
MOA of Oxycodone
potency
- full MOR agonist
1. 5
MOA of heroin
potency
- full MOR agonist
2
MOA of Buprenorphine
used for
negative effects
when do we give it
- partial MOR agonist (more potent)
- full kappa and delta antagonist
- reduces withdrawal symptoms without producing same level of addictive effects
- more potent and will displace opioids from receptor if taken at the same time precipitating withdrawal symptoms
- after withdrawal symptoms begin
MOA of Nalbuphine
- partial MOR agonist
- full kappa agonist
MOA of Methadone
potency
used for/benefits
negative effects
- full MOR agonist
1
- reduce withdrawal symptoms and ease detox
- long biological half life (24 hours)
- can be addictive
MOA of Meperidine
potency
- full MOR agonist
0. 1
MOA of fentanyl
potency
- full MOR agonist
100
MOA of Remifentanil
potency
- full MOR agonist
200
MOA of carfentanil
potency
- full MOR agonist
10000
MOA of Butorphanol
- partial MOR agonist
- full kappa agonist
MOA of methylnaltrexone
what does it treat
- neutral MOR antagonist
- inhibit effects of other opioids through competition for receptor binding
- opioid induced constipation
MOA of pentazocine
- neutral MOR antagonist
- full kappa agonist
MOA of Naltrexone
used for
- inverse MOR agonist
- inhibit basal, opioid-independent activity of the receptor
- treat acute opioid overdoses
MOA of Naloxone
used for
- inverse MOR agonist
- inhibit basal, opioid-independent activity of the receptor
- treat acute opioid overdoses
what happens in transduction step of pain
- nociceptors increase rate of depolarization in response to noxious stimulus
what happens in the modulatory step of pain
- descending pathway of nerve impulse modules pain perception
both the ascending and descending pathway intersect where
what is this the site of
- in the dorsal horn of the spinal cord
- summation of intensity of pain
- site of opioid action
endorphins act on which opioid receptor
- mu
enkephalins act on which opioid receptor
- delta
dynorphins act on which opioid receptor
- kappa
opioids produce analgesia by agonizing receptors in the
- brain and spinal cord
- peripheral nociceptor neurons
opioids produce sedation and respiratory depression by acting on receptors in the
- brain
opioids produce constipation by acting on receptors in the
- myenteric/submucosal plexus of the enteric nervous system in the GI tract
can partial agonists produce full analgesia
- no, but still clinically useful
oral administration of opioids subjects them to the ____-
- first pass effect
opioids are metabolized by what reactions
what is the product
eliminated by
significance of the product
- phase I/phase II
- highly polar glucuronidated metabolites
- eliminated by kidneys
- can have more potent analgesic effects or more toxicity
some opioids can be metabolized into ______ drugs through ______ mediated reactions
which ones
- more potent
- CYP2D6
- codeine, hydrocodone, and oxycodone
what opioids are okay to use in a patient with renal dysfunction
- fentanyl
- methadone
- burprenoprhine
MORs are found on the ___-synaptic nociceptor neuron terminal and ____-synaptic cell membrane
- presynaptic nociceptor neuron terminal
- postsynaptic cell membrane
MOA of opioid-activated MORs in presynaptic neuron
- inhibit opening of Ca2+ channels during depolarization
- reduce influx of Ca2+
- slow release of neurotransmitters
MOA of opioid-activated MORs in postsynaptic neuron
- stimulate opening of K+ channels
- increase K+ efflux
- hyper polarize the neuron
opioid action on descending modulatory pathway
- block release of GABA
- disinhibit modulatory neurons
toxicities of acute opioid use
how
- respiratory depression
- constipation
- sedation
toxicities of chronic opioid use
how
- hyperalgesia - increase sensitivity to noxious stimuli
- tolerance - inactivated receptor
- dependence - release dopamine into nucleus accumbens in mesolimbic pathway. (inhibit release of GABA that negatively regulates this process)
- withdrawal
how do opioids cause respiratory depression
- MORs on respiratory control centers of pons and medulla.
- reduce signaling to diaphragm and intercostal muscles
- slow rate of breathing
how do opioids cause sedation
- bind to MORs in brain and cause sedation
how do opioids cause constipation
can be beneficial in patients with
- bind to MORs on myenteric and submucosal plexus in the GI tract which coordination smooth muscle contraction
- inhibit transmission and reduce GI smooth muscle contraction
- diarrhea
what is cross tolerance
- tolerance to one opioid producing tolerance to others
what is opioid rotation
- switch to a different opioid after tolerance develops from previous one
peak symptoms of opioid withdraw begin to subside by
- 3-4 days
importance of naloxone being administered nasally
- increases rate of absorption
- minimizes onset time
Suboxone combines
MOA
how is it given
- buprenorphine with naxolone
- block effects of drug being abused
- mitigate symptoms of withdrawal
- sublingual
drugs that inhibit/induce _____ or ____ can have drug reactions with opioids
- CYP3A4/2D6
drugs that inhibit CYP3A4/2D6
- cardiac drugs (amiodarone, diltaizem, verapamil)
- behavioral drugs (bupropion, SSRIs)
- GI drugs (cimetidine)
- antibiotics (fluoroquinolones)
drugs that induce CYP3A4/2D6
- anticonvulsants (barbiturates, phenytoin)
- anti-inflammatories (corticosteroids)
- behavioral drugs (duloxetine)
