*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

Which receptors that Opioid Agonist-Antagonists binds to and their effects?

A

µ receptors: partial effect (agonist) or no effect (competitive antagonist)

Κ and δ receptors: partial effect (agonist)

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3
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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4
Q

How potent is Pentazocine?

A

1/5 as potent as Morphine

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5
Q

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

A
  • κ & δ receptor
    -Agonist effects with weak antagonist activity

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6
Q

What is Pentazocine antagonized by?

A

Naloxone

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7
Q

What is the elimination 1/2 time of Pentazocine?

A

2 - 3 hours

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8
Q

How is Pentazocine excreted?

A

Glucuronide conjugates in the urine.

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9
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
  • 20-30mg IM= 10mg Morphine

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10
Q

What is the epidural analgesia duration of Pentazocine?

A

Shorter duration < Morphine

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11
Q

What are the side effects of Pentazocine?

A
  • sedation
  • diaphoresis
  • dizziness
  • dysphoria (high doses)
  • increased HR, BP, PA bp, LVEDP

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12
Q

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

A

Pentazocine

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13
Q

What type of drug is Butorphanol?

A

Agonist 20x and antagonist 10x to 30x > Pentazocine

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14
Q

What receptors does Butorphanol bind to?

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

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15
Q

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

A

Dysphoria

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16
Q

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

A

10

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17
Q

By what route is butorphanol rapidly and completely absorbed?

A

Intramuscular

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18
Q

Where is Butorphanol excreted?

A

Bile > urine

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19
Q

What are the side effects of Butorphanol?

A
  • sedation
  • nausea
  • diaphoresis
  • dysphoria
  • depression of ventilation
  • withdrawal symptoms occur
  • increased BP, PA BP, & C0

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20
Q

What is the caution with Butorphanol?

A

difficult to use with another opioid agonist

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21
Q

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

A

μ receptor agonist that is equipotent to Morphine.

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22
Q

Where is Nalbuphine metabolized?

A

Liver

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23
Q

What is the elimination 1/2 time of Nalbuphine?

A

3 to 6 hours

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24
Q

What are the side effects of Nalbuphine?

A
  • sedation
  • dysphoria
  • withdrawal symptoms

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25
Q

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

A
  • Nalbuphine
  • No increase in BP, pBP, HR or atrial filling.

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26
Q

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

A

Buprenorphine

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27
Q

Analgesic potency of ____ mg IM of Buprenorphone = 10 mg Morphine?

A

0.3 mg IM

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28
Q

What is Buprenorphine’s onset?
Duration?

A
  • 30min onset
  • 8 hour duration

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29
Q

What is Buprenorphine’s used for?

A
  • Post op
  • cancer
  • renal colic
  • MI
  • epidural

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30
Q

Which two drugs have resistance to Naloxone?

A
  • Buprenorphine and Bremazocine.

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31
Q

Opioid Agonist-Antagonist

What are drug facts of Nalorphine?

A
  • equally potent with Morphine
  • Not used clinically: high incidence of dysphoria (σ receptors)

S14

32
Q

Opioid Agonist-Antagonist

What are drug facts of Bremazocine?

A
  • κ receptors 2x potent > Morphine
  • Naloxone = not effective as reversal (could be other receptors)

S14

33
Q

Opioid Agonist-Antagonist

What are drug facts of Decozine?

A
  • δ & µ: analgesia, no CV
  • 0.15 mg/kg IM= Morphine
  • 10 to 15 mg IM rapid absorption
  • Onset: 15 mins.

S14

34
Q

What are drug facts of Meptazinol?

A
  • mu1 receptors
  • 100 mg = 8 mg Morphine
    ** Rapid onset
  • Duration: < 2 hrs
  • Protein binding: 25%

S14

35
Q

Which drugs are pure μ-opioid receptor antagonists?

A
  • Naloxone
  • Naltrexone
  • Nalmefene

Competitive antagonist –> High affinity to opioid receptors

S18

36
Q

What receptors is Naloxone effective on?

A
  • μ, κ, δ (non-selective)

S19

37
Q

What are the uses of Naloxone?

A
  • opioid-induced depression in post op
  • neonate* (from mom)
  • opioid overdose
  • detect dependence

S19

38
Q

What non-opioid uses does Naloxone have?

A
  • ↑ contractility for shock
  • Antagonism of general anesthesia (at high doses)
39
Q

What is the naloxone IV push dose?
Continuous infusion?

A

1-4 mcg/kg IVP

S20

40
Q

What is the continuous infusion of Naloxone?

A

5 mcg/kg IV infusion

S20

41
Q

What dose of naloxone is use for shock?

A

> 1mg/kg IV

42
Q

What dose will cause epidural side effect of Naloxone?

A

0.25 µg/kg/hour IV

S20

43
Q

How long does Naloxone last?

A
  • 30 - 45 minutes

Often needs redosing for overdoses.

S20

44
Q

What are the possible side-effects of naloxone?

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

S20

45
Q

Where is Naloxone metabolized and the first pass effect?

A

metabolized in Liver (glucorinic acid)

1/5th PO Hepatic first pass

S20

46
Q

What is the elimination 1/2 time of Naloxone?

A

60 to 90 mins

S20

47
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.

S21

48
Q

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

A
  • Nalmefene = naloxone
  • 15 - 25 mcg IV (max of 1 mcg/kg)

S21

49
Q

What is the elimination 1/2 time of Nalmefene?

A

10.8 hours

S21

50
Q

What is Methylnaltrexone’s use?

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

S22

51
Q

What is Alvimopan and what is it used for?

Why can’t it be used long term?

A
  • μ-selective PO peripheral opioid antagonist for post-op ileus.
  • CV problems long term

S22

52
Q

Where is Alvimpan metabolized?

A

gut flora

S22

53
Q

What are the abuse-resistant opioid formulations?

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

S23

54
Q

What causes immunosuppression with Opioid use?

A
  • Prolonged exposure to opioids
  • abrupt withdrawal

Less in short term opioid use

S24

55
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.

S25*

56
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.

S25*

57
Q

Which Opioid Agonist-Antagonists have an effect on MAC?

A
  • Pentazocine (20%)
  • Butorphanol (11% decrease)
  • Nalbuphine (8% decrease)

S25

58
Q

Where are receptors targeted with opioid neuraxial anesthesia?

A

Opioid receptors of the substantia gelatinosa.

S28*

59
Q

Neuraxial Opioids can be used on what sites?

A
  1. Epidural
  2. Subarachnoid/Spinal/Intrathecal

S29*

60
Q

What is general rule of dosing for epidural opioids?

A
  • Dose = 5 - 10 x normal

S29*

61
Q

Which Neuraxial Opioid drug has slower onset but longer duration?

A

Morphine

S29

62
Q

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

A

dura mater

S30*

63
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.

S30*

64
Q

What is Cephalad movement (in regards to epidurals)?

A

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

S31*

65
Q

What drug attribute decreases cephalad movement?

A

Lipid solubility

S31

66
Q

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

A

Morphine > Fentanyl & Sufentanil

  • Fentanyl and it’s derivatives are much more lipid soluble and thus exhibit less cephalad movement.

-More in spinal cord < remains in CSF and migrate cephalad

S31

67
Q

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

A

Coughing and/or straining

S31

68
Q

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

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

S32*

69
Q

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

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

S32*

70
Q

When would 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)

S32

71
Q

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

A
  • Pruritis
  • Cephalad migration to trigeminal nucleus

most common in OB

S33

72
Q

What are the treatments for pruritis induced by neuraxial opioids?

A
  • 10mg Propofol
  • Naloxone
  • Antihistamines
  • Gabapentin

S33

73
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
  • Neonatal effects.

S33 to S35

74
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

S34

75
Q

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

A
  • 2 - 5 days

S35