Opioid Agonist-Antagonists & Antagonists (Exam II) Flashcards

1
Q

What is the primary indication for opioid agonist-antagonists?

A
  • Used if unable to tolerate full agonist
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2
Q

Name the four advantages of opioid agonist-antagonists.

A
  • Analgesia
  • Less respiratory depression
  • Low dependence potential
  • Ceiling effect (prevents ODing)
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3
Q

How potent is Pentazocine?

A
  • 1/5 as potent as morphine/nalorphine
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4
Q

What receptors does pentazocine bind to?
What type of activity does it exhibit?

A
  • κ & δ receptor partial agonist activity
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5
Q

How is pentazocine excreted?

A
  • Glucuronide conjugates in the urine.
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6
Q

Which opioid agonist-antagonist crosses the placental barrier causing fetal depression?

A

Pentazocine

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7
Q

What is the chronic pain dose of Pentazocine?
What dose and route would be equivalent to morphine 10mg?

A
  • 10 - 30mg IV or 50 mg PO ( = codeine 60mg)
  • 20-30mg IM = 10mg morphine
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8
Q

Where is butorphanol excreted?

A

Bile

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9
Q

What receptors does butorphanol bind to?

A
  • κ = analgesia & anti-shivering
  • μ (low)
  • σ (low)
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10
Q

Sigma (σ) receptors are associated with what side effect?

A

Dysphoria

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11
Q

2 to 3 mg of butorphanol is equivalent to _____ mg of morphine.

A

10

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12
Q

By what route is butorphanol rapidly and completely absorbed?

A

Intramuscular

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13
Q

What drug is an excellent choice for cardiac catheterization patients?
Why?

A
  • Nalbuphine
  • No increase in BP, pBP, HR, atrial filling pressures.
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14
Q

What receptors does nalbuphine bind to?
How potent is it?

A
  • μ receptor agonist that is equipotent to morphine/nalorphine.
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15
Q

Which agonist-antagonist has 50 times greater μ receptor affinity than morphine?

A

Buprenorphine

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16
Q

What is buprenorphine’s onset?
Duration?

A
  • 30min onset
  • 8 hour duration
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17
Q

What is buprenorphine’s greatest use?

A
  • post op, cancer, renal colic, MI; epidural
  • Opioid use disorder (has low risk of abuse)
  • duration 8hr
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18
Q

Which two drugs have resistance to naloxone?

A
  • Buprenorphine and *Bremazocine.
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19
Q

Which opioid has high incidence of dysphoria and is therefore not utilized clinically?

A

Nalorphine

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20
Q

Which drugs are pure μ-opioid receptor antagonists?

A
  • Naloxone
  • Naltrexone
  • Nalmefene
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21
Q

What receptors is naloxone effective on?

A
  • μ, κ, δ (non-selective)
22
Q

What non-opioid uses does naloxone have?

A
  • ↑ contractility for shock
  • Antagonism of general anesthesia at high doses.
23
Q

What is the naloxone IV push dose?
Continuous infusion?

A
  • 1-4 mcg/kg IV
  • 5 mcg/kg IV infusion
24
Q

What dose of naloxone is use for shock?

A
  • > 1mg/kg IV
25
Q

How long does Naloxone last?

A
  • 30 - 45 minutes

Often needs redosing for overdoses.

26
Q

What are the possible side-effects of naloxone?

A
  • Analgesia reversal
  • N/V
  • ↑ SNS ( ↑ HR, BP, dysrhythmias, etc.)
  • pulmonary edema
27
Q

What use does naltrexone have?
How long does it last and how is it adminstered?

A
  • EtOH
  • Given PO (more effective) lasts for 24 hours.
28
Q

How does nalmefene’s potency compare to naloxone?
What is it’s dose and max?

A
  • Nalmefene = naloxone
  • 15 - 25 mcg IV q 2-5 min (max of 1 mcg/kg)
  • E1/2 10.8 hr
29
Q

What is methylnaltrexone’s use?

A
  • Anti-emetic (antagonizes N/V from opioids)
  • promotes gastric emptying
30
Q

What is Alvimopan and what is it used for?
How is it metabolized?
Why can’t it be used long term?

A
  • μ-selective PO peripheral opioid antagonist for post-op ileus.
  • Gut flora metabolism
  • CV problems long term
31
Q

What are the abuse-resistant opioid formulations?

A
  • Suboxone (buprenorphine + naloxone)
  • Embeda (long-release morphine + naltrexone)
  • OxyNal (oxycodone + naltrexone)
32
Q

What opioids-agonists have a significant effect on volatile anesthetics?
What do they do?

A
  • Fentanyl & it’s derivatives decrease the MAC of volatiles by 50% or greater.
33
Q

Fentanyl 3 μg/kg IV 25-30 min prior to incision will have what effect on which volatile gasses?

A
  • 50% MAC reduction for isoflurane and desflurane.
34
Q

Which opioid partial agonists have an effect on MAC?

A
  • Pentazocine 20%
  • Butorphanol 11%
  • Nalbuphine 8%
35
Q

Where are receptors targeted with opioid neuraxial anesthesia?

A
  • Opioid receptors of the substantia gelatinosa.
36
Q

What is general rule of dosing for epidural opioids?

A
  • Dose = 5 - 10 x normal
37
Q

Diffusion of opioids across the _____ ______ results in systemic absorption.

A

dura mater

38
Q

Where can opioids be injected during an epidural that results in systemic absorption?
What should be done if this occurs?

A
  • Epidural venous plexus
  • Add epi to the infusion.
39
Q

What is Cephalad movement (in regards to epidurals)?

A

Cephalad Movement = the movement of drug/injectate up the spinal cord towards the brain.

40
Q

What drug attribute decreases cephalad movement?

A
  • Lipid solubility
41
Q

________ exhibits much more cephalad movement than __________.
Why is this?

A
  • Morphine ; fentanyl
  • Fentanyl and it’s derivatives are much more lipid soluble and thus exhibit less cephalad movement.
42
Q

What can cause cephalad movement? (besides characteristics of drugs themselves)

A

Coughing and/or straining

43
Q

When would epidural CSF levels peak for the following drugs:
- Fentanyl
- Sufentanil
- Morphine

A
  • Fentanyl - 20min
  • Sufentanil - 6min
  • Morphine - 1-4 hours
44
Q

When would epidural administered plasma levels peak for the following drugs:
- Fentanyl
- Sufentanil
- Morphine

A
  • Fentanyl - 5-10 min
  • Sufentanil - 5 min or less
  • Morphine - 10 - 15 min
45
Q

When would epidural administered intrathecal/cervical CSF levels peak for the following drugs:
- Fentanyl
- Sufentanil
- Morphine

A
  • Fentanyl - N/A
  • Sufentanil - N/A
  • Morphine - 1 - 5 hours (due to cephalad movement)
46
Q

What is the most common side effect from neuraxial opioid administration?
Why does this occur?

A
  • Pruritis
  • Cephalad migration to trigeminal nucleus
47
Q

What are the treatments for pruritis induced by neuraxial opioids?

A
  • 10mg Propofol
  • Naloxone
  • Antihistamines
  • Gabapentin
48
Q

Name the list (its a lot) of side effects that can occur with neuraxial opioid administration.

A
  • Pruritis
  • N/V
  • Urinary retention
  • Respiratory depression
  • Sedation
  • Skeletal muscle rigidity
  • Herpes virus reactivation (2-5 days)
  • Neonatal effects. (Negligible in breast milk)
49
Q

If neuraxial opioids induced a reemergence of a herpes virus, how long would this occur after opioid administration?

A
  • 2 - 5 days
50
Q

What sign would indicate respiratory depression from neuraxial opioid administration?

What is the treatment?

A
  • ↓LOC from ↑CO₂
  • Naloxone 0.25 μg/kg/hr IV