Opioid Agonist-Antagonists & Antagonists (Exam II) Flashcards
What is the primary indication for opioid agonist-antagonists?
- Used if unable to tolerate full agonist
Name the four advantages of opioid agonist-antagonists. This will probably be super important
- Analgesia
- Less respiratory depression
- Low dependence potential
- Ceiling effect (prevents ODing)
How potent is Pentazocine?
- 1/5 as potent as Nalorphine (Nalorphine is as potent as morphine)
What receptors does pentazocine bind to?
What type of activity does it exhibit?
- Agonizes κ & δ receptors with weak antagonist activity (partial agonist activity?)
Antagonized by Naloxone
How is pentazocine excreted?
- Glucuronide conjugates in the urine.
Extensive hepatic first pass (20% available post PO)
- Elimination half-time: 2 to 3 hours
Which opioid agonist-antagonist crosses the placental barrier causing fetal depression?
Pentazocine
What is the chronic pain dose of Pentazocine?
What dose and route would be equivalent to morphine 10mg?
- 10 - 30mg IV or 50 mg PO (equivalent to Codeine 60 mgs)
- 20-30mg IM = 10mg morphine (watch for similar analgesia, sedation, and respiratory depressive effects)
How much longer (than morphine) does Pentazocine act when administered epidurally?
Trick question, morphine has a longer duration epidurally :)
What are some of pentazocine’s S/E?
sedation (duh), diaphoresis, dizziness, dysphoria in high doses (b/c δ receptor activation).
- Also increased HR, BP, LVEDP, and Pulm. Art Pressure
Where is butorphanol metabolized?
Excreted?
Elim. Half-Time?
- Liver
- Bile>urine
- 2.5-3.5hrs
What receptors does butorphanol bind to?
- κ = analgesia & anti-shivering
- μ (low, producing antagonism)
- σ (minimal so low dysphoria effects)
Sigma (σ) receptors are associated with what side effect?
Dysphoria
IM 2 to 3 mg of butorphanol is equivalent to _____ mg of morphine.
10
Don’t confuse IM dose of butorphanol (2-3mg) with pentazocine (20-30mg
By what route is butorphanol rapidly and completely absorbed?
Intramuscular
Which receptor has a moderate affinity for butorphanol’s effects to mitigate shivering and produce analgesia?
Kappa
What is Nalbuphine’s Elim. Half-Time?
3-6hrs
What drug is an excellent choice for cardiac catheterization patients?
Why?
- Nalbuphine
- No increase in BP, PA BP, HR or atrial filling pressures!
u in Nalbuphine for µ receptor
What receptors does nalbuphine bind to?
How potent is it?
- μ receptor agonist that is equipotent to morphine.
Dr. Castillo felt it important to state that as an antagonist, Nalbuphine is 1/4th as potent as Nalorphine
Which agonist-antagonist has 50 times greater μ receptor affinity than morphine?
Buprenorphine
u in Buprenorphine for µ receptor
What is buprenorphine’s onset?
Duration?
- 30min onset
- 8 hour duration (has prolonged resistance to Naloxone)
What is buprenorphine’s greatest use?
- Opioid use disorder (has low risk of abuse)
Does Buprenorphine have any side effects?
Of course, it’s an opiate. Pretty standard though…
- Drowsiness
- N/V
- Ventilation depression
- Pulmonary edema
- Withdrawals but low risk of abuse.
It is typically used to treat opioid use disorders
Which two drugs have resistance to naloxone?
- Buprenorphine and Bremazocine.
Which opioid has high incidence of dysphoria and is therefore not utilized clinically?
Nalorphine (σ receptors)
- Nalorphine is equally potent with Morphine
o in NalOrphine for σ receptor. Get it? sigma looks kin of like a o. No? Ok then.