opioid agonist-antagonist Flashcards
name the 5 agonists/antagonists we need to know
- Pentazocine (Talwin)
- Butorphanol (stadol)
- Nalbuphine (Nubain)
- Buprenorphine (Buprenex)
- Buprenorphine/Naloxone (Suboxone)
reversibly binds
receptor at same site as agonist but does NOT
activate receptor.
competitive antagonist
what are the effects from competitive antagonists from?
preventing agonists from binding
to and activating the receptor
what does the clinical response of competitive antagonists depend on?
the concentration of agonists in the system that the drug has to compete with to bind to receptor site
irreversibly binds
receptor at a separate site from agonists.
Non-competitive antagonists
think non-comp = drug does not care about winning receptor
2 important things that Non-competitive antagonists do
– Inhibits the full agonist response
Prevents conformational changes in receptor which
are required for receptor activation.
Drug has a high affinity for the receptor but not
so much intrinsic activity
Partial agonist
this type of drug binds to a receptor but causes a decrease in receptors response
• Partial agonist
greater effects at the receptor than the defining receptor agonist (morphine)
Superagonist
*fent vs morphine
Opioid Agonists/Antagonists have most Successful use in these type of patients
opioid addiction/chronic use population
Opioid Agonists/Antagonists have what effect on morphine and pure agonists?
Produce a degree of competitive antagonism
to morphine and pure agonists
What type of pain are opioid agonist/antagonists appropriate for?
acute & chronic pain
even tho agonist/antagonists are Synthetic or semi-synthetic analgesics, what drug are they structurally r/t?
morphine
what characteristics to ag/ant have on mu receptor (broad)
Partial µ agonist producing limited to no effects (less resp depression)
what two receptors do ag/ant effect most?
kappa and delta!
what is the cool thing about ag/ant?
Reverses opioid overdose while continuing to
provide analgesia
are Opioids that have antagonist effects on µ and к
receptors useful in pain management?
Yes
6 Benefits of Opioid Agonists/Antagonists
- great when pt cant tolerate full agonist
- analgesia (k) without resp depression (mu)
- used in pt with opioid dependency hx
- ceiling effects limit toxicity of drug
- no significant elevation of interbiliary pressure
- less constipation
because ag/ant do not cause significant elevation of interbiliary pressure, what pts are these good for?
Useful in patients with biliary colic
kappa receptors main side effect
Psych
dysphoria
will giving morphine after giving an ag/ant work well for analgesia?
Subsequent doses of agonist after opioid A/A may NOT provide
adequate analgesia
3 undesirable effects from kappa receptor
- dysphoria, confusion (elderly)
- no euphoria
- depression
these ag/ant are typically not appropriate for what patient population?
cards because of catecholamine release so increase in BP, CO
in regards to ceiling effect of response with ag/ant:
Depression of ventilation (advantage)
– Weak ability to decrease anesthetic requirement, really not great for “balanced” anesthesia plan
what receptor antagonist can lead to withdrawal
mu
CNS effects of kappa receptor
depression sedation dysphoria hallucinations delirium
what does the kappa receptor cause in the GU system that other receptors do not?
diuresis due to inhibition of vasopressin
Weak antagonist of µ receptors, partial к agonists that does not antagonize resp depression
Pentazocine(Talwin)
what 2 meds can be antagonized by narcan
- Talwin (pentazocine)
- nubain (nalbuphine)
indications of pentazocine
– Relief of moderate pain
– Chronic pain & increase risk of physical dependence.
Antagonist effects of talwin cause
withdrawal in patients
chronically receiving opioids
Effects of pentazocine (talwin)
Analgesia, sedation, mild resp.depression
CNS side effects of Pentazocine(Talwin)?
*dose dependent
Sedation, dysphoria, diaphoresis, dizziness, dissociation
“weird” feelings, hallucinations, NO mood elevation
can pentazocine cross the placenta?
YES! potentially causing fetal depression
P=Placenta
cards side effects of Pentazocine(Talwin)
– ↑HR & cardiac workload(catecholamine release) ↑SBP &
pulmonary artery pressure, ↑ myocardial O2 consumption
*Butorphanol(Stadol) is More potent agonist & antagonist than Talwin by what amount
Agonists 20x
Antagonists 10-30x greater
what ag/ant has more potent analgesia than morphine?
Butorphanol(Stadol)
Indications for butorphanol (stadol)
Post-op pain and migraine headaches.
– Post op shivering
S=S [shivering]
Equal doses of Butorphanol(Stadol)?
Analgesia & respiratory depression =10
mg Morphine or 80-100 mg Demerol.
side effects include sedation, nausea, diaphoresis, resp. depression, dissociation, rarely dysphoria
Butorphanol(Stadol)
– CV side effects of stadol
: ↑Cardiac Output and cardiac
workload, ↑SBP and pulmonary artery pressure.
why does stadol RARELY cause dysphoria?
because there are MULTIPLE kappa receptors
Potency comparable to morphine
*Nalbuphine(Nubain)
what makes Nalbuphine(Nubain) really cool?
*No ill-effects on CV patients.
Nalbuphine(Nubain) is a µ receptor antagonist and к receptors agonist which means (3 points)
– Subsequent morphine dosing less effective
– Useful in reversing lingering fentanyl-induced respiratory depressant effects while providing satisfactory analgesia.
– Antagonizes pruritus induced by epidural morphine.
withdrawal can occur with whats ag/ant?
nubain - nalbuphine talwin - pentazocine stadol - butorphanol buprenorphine - buprenex suboxone (least amount) literally all of them
• Effects of Nalbuphine(Nubain)?
Analgesia, sedation, diaphoresis, headache
what receptor agonist effects provide adequate pain relief with
less respiratory depression with nubain
kappa
Side Effects of nalbuphine - nubain
sedation (33%)
resp depression
dissociation
µ receptor affinity 50x greater than morphine
Buprenorphine(Buprenex)
this ag/ant has a Prolonged duration up to 8 hours
Buprenorphine(Buprenex)
does narcan work with buprenorphine - buprenex?
Resistant to antagonism
Indications for buprenex
– Effective on moderate to severe cancer pain.
– Opioid dependence (really the best)
Side effects of Buprenorphine(Buprenex)
Sedation, N/V, diaphoresis, HA, dizziness
what drug class does buprenorphine - buprenex interact with?
Benzos
B=B
Buprenorphine(Buprenex effect what receptors and in what way
- Partial µ receptor agonist.
* Antagonizes µ and k receptors
– partial μ-agonist and full κ-antagonist in a fixed 4:1
ratio with naloxone
Buprenorphine/Naloxone (Suboxone)
Alternative to methadone for addicted patients and why?
Buprenorphine/Naloxone (Suboxone)
– Less resp depression, better safety, less withdrawal
in general, pts had a what % decrease in cravings for opioids when taking suboxone
40% - big time
suboxone is a analgesic that provides very little pain relief
for non-opioid dependent or addicted patients why?
Because suboxone works to reduce hyperalgesia and non-opioid patients don’t
have hyperalgesia like opioid patients do.
Pain is exaggerated and prolonged in response
to noxious stimuli
Hyperalgesia
what two patient populations has suboxone been proven to be effective with
opioid addiction without chronic pain
opioid addiction with chronic pain
when pt comes in on suboxone what do you expect their anesthesia care plan to include?
Requires a higher dose of opioid needed to
achieve adequate pain control
why does suboxone Requires a higher dose of opioid needed to achieve adequate pain control
• Can block other opioids from activating the
same opioid u receptors
• Some recommend replacing suboxone with
other opioids preoperatively for how many days?
3-7 days then
re-initiating suboxone therapy
