Opioids Agonists (Exam II) Flashcards

1
Q

What are opioids effects on the CO₂ medullary center?

A
  • Opioids inhibit the CO₂ medullary center.
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2
Q

Differentiate opioids from narcotics.

A
  • Opioids = all exogenous substances that bind to endogenous opioid receptors.
  • Narcotic = any substance that can produce dependence (stupor)
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3
Q

What two types of opioid chemical structures are there?

A
  • Phenanthrenes
  • Benzylisoquinolines
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4
Q

What types of drugs are Phenanthrenes?
What types of drugs are benzylisoquinolines?

A
  • Phenanthrenes: Morphine & codeine
  • Benzylisoquinoline: Papaverine
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5
Q

What is papaverine mostly used for?

A

Treating intra-arterial barbiturate administration (dilates the highly constricted artery).

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6
Q

What portions of the brain are the source of descending inhibitory signals?

A
  • Thalamus
  • PAG
  • Locus Coeruleus
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7
Q

What endogenous substances have the same effect as opioids?

A

Endorphins, Enkephalins, and Dynorphines.

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8
Q

Presynaptic inhibition of what neurotransmitters occurs with opioid administration?

A
  • ACh
  • Dopamine
  • NE
  • Substance P
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9
Q

How do opioids modulate pain at the cellular level?

A
  • ↑ pK⁺ (hyperpolarization)
  • Ca⁺⁺ channel inactivation
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10
Q

Where are opioid receptors located in the brain?

A
  • PAG
  • Locus Ceruleus
  • RVM (rostral ventral medulla)
  • Hypothalamus
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11
Q

Where is the primary site of opioid receptors in the spinal cord?

A

Substantia gelatinosa (aka Laminae 2)

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12
Q

Where is/are opioid receptors found outside the CNS?

A
  • Sensory neurons & immune cells
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13
Q

What are the four (most important) types of opioid receptors?

A
  • Μu1 (μ₁)
  • Μu2 (μ₂)
  • Κappa (κ)
  • Delta (δ)
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14
Q

Which opioid receptor(s) is/are responsible for respiratory depression & physical dependence?

A
  • Μu2 and δ
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15
Q

Which receptors are responsible for constipation?

A
  • Μu2 primarily
  • δ (less)
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16
Q

Which receptors can cause urinary retention?
Are there any receptors that cause diuresis when bound?

A
  • Retention: Μu1 and δ
  • Diuresis: κ
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17
Q

All opioid receptors induce analgesia at both the brain the spinal cord. T/F?

A
  • False. Μu2 receptors only cause at analgesia at the spinal cord level.
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18
Q

What opioid receptors have low abuse potential when bound?

A

Μu1 and κ

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19
Q

Which opioid receptor is responsible for euphoria, bradycardia, hypothermia, and miosis when bound?

A

Mu1

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20
Q

What agonists bind to the four opioid receptors?

A
  • Mu1 & Mu2 = endorphins, morphine, synthetics.
  • κ = dynorphins.
  • δ = enkephalins.
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21
Q

Describe the adverse side effects of opioids on the cardiovascular system.

A
  • ↓BP from ↓SNS tone
  • ↓HR + histamine release = ↓BP
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22
Q

What possible cardiovascular benefits do opioids provide?

A
  • Myocardial ischemia protection (won’t cause myocardial depression)
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23
Q

What are the respiratory effects of opioids?
What would symptoms of overdose be?

A
  • Depressed CNS response to CO₂ causing a right shift of PaCO₂ (↑)
  • Overdose = apnea, miosis, ↓RR, coma.
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24
Q

What drug would treat opioid ventilatory depression but not reverse analgesia?
How?

A
  • Physostigmine would by increasing CNS ACh levels.
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25
Q

What is normal PaO₂?
What shift in PaO₂ would be seen with metabolic acidosis?
What shift in PaO₂ would be seen with general anesthesia?

A
  • Normal PaO₂ is 80 mmHg
  • Left shift
  • Right shift
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26
Q

What would cause a leftward shift in PaO₂?
What would cause a rightward shift?

A
  • Leftward: Metabolic acidosis (to breathe off all that CO₂)
  • Rightward: sleep → opiates → anesthesia
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27
Q

Why should caution be used when administering opioids to head trauma patients?

A
  • Opioids ↓CBF and possibly ICP
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28
Q

What musculoskeletal abnormality occurs with opioid administration?
What makes this condition worse?
How is it treated?

A
  • Skeletal chest wall and abdominal muscle rigidity.
  • Mechanical ventilation
  • Muscle relaxants and/or naloxone
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29
Q

What are sphincter of Oddi spasms?
Which drugs can cause this?

A
  • Biliary smooth muscle spasm
  • Fentanyl (99%), Morphine (53%), and Meperidine (61%).

I think maybe all opioids can cause this but these are the primary culprits

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30
Q

What drugs should be used for ERCP cases?

A
  • Non-opioids (multimodal approach w/ NSAIDs, gabapentin, etc.)
31
Q

How are opioid-induced sphincter of Oddi spasm’s treated?

A
  • Naloxone
  • Glucagon (2mg IV given incrementally) and causes no opioid antagonism.
32
Q

How long does it take (generally) to develop tolerance to opioids?
What causes tolerance?

A
  • 2-3 weeks
  • Downregulation
33
Q

What is the dosage of morphine?
When does it peak?
How long does it last?

A
  • 1 - 10 mg IV
  • Peak: 15 - 30 minutes
  • Duration: 4 hours
34
Q

How is morphine metabolized?
What is the active metabolite and its significance?

A
  • Glucuronidation in the kidneys.
  • Morphine-6-glucuronide = comprises only 5-25% of morphine metabolites but is an active anaglesic causing late resp depression.
35
Q

What would occur with morphine overdose in a renal failure patient?

A
  • Prolonged ventilatory depression.
36
Q

What receptors does meperidine agonize?

A
  • μ and κ receptors
  • α2 receptors as well
37
Q

What are the analogues of meperidine?
What other drugs does meperidine have a similar organic structure to?

A
  • Fentanyl & it’s derivatives
  • Lidocaine & Atropine
38
Q

How potent is Meperidine?
How long does it last?

A
  • 10% as potent as morphine
  • Duration: 2-4 hours
39
Q

What is the primary indication for meperidine?
What dose is used?

A
  • Post-operative shivering
  • 12.5mg IV
40
Q

When should meperidine not be used?

A
  • Bronchoscopies (promotes coughing)
41
Q

How potent is fentanyl?

A
  • 75 - 125 x morphine.
42
Q

What is the blood-brain equilibration of fentanyl?
What does this mean?

A
  • 6.4 minutes
  • Potent with rapid onset and ↑ lipid solubility.
43
Q

What percent of fentanyl is subject to lung first-pass effect?
What does this mean?

A
  • 75%
  • Drug is taken up into lung tissue and possibly subjected to breakdown via pulmonary esterases.
44
Q

Where is fentanyl metabolized?
What is its principal metabolite?

A
  • Liver via CYP3A
  • Norfentanil
45
Q

How does fentanyl dosing change for the elderly or liver patients?

A

No change in elderly or cirrhotic patients.

46
Q

Describe what the graph below is showing.

A

Fentanyl has the greatest context-sensitive half-time of any of the fentanyl derivatives.

47
Q

What is the analgesia dosage of fentanyl?
Induction dose?

A
  • Analgesia: 1 - 2 μg/kg IV
  • Induction: 1.5 - 3 μg/kg IV
48
Q

1mg of PO fentanyl = ____ mg of IV morphine

A

5

49
Q

What is the intrathecal dosage of fentanyl?

A

25 mcg

50
Q

What is the adult oral dose of fentanyl?
Pediatric?

A
  • Adult: 5 - 20 mcg/kg
  • Peds: 15 - 20 mcg/kg
51
Q

What is the transdermal dose of fentanyl?

A
  • 75 - 100 μg (18 hours steady state)
52
Q

What cardiovascular side effects should be known about fentanyl?
What CNS side effects should be known?

A
  • ↓BP & ↓CO
  • Can cause seizures & modestly increase ICP.
53
Q

How much more potent is sufentanil than fentanyl?

A
  • 5-12 times more potent.
54
Q

How much of sufentanil is subject to first pass effects?

A
  • 60% lung first-pass
55
Q

How much of sufentanil is protein bound? What protein is it bound to?

A

92.5% α-1 acid glycoprotein bound.

56
Q

What is the analgesia dose of sufentanil?

A
  • Analgesia: 0.1 - 0.4 μg/kg IV
57
Q

What is the induction dose of sufentanil?

A

18.9 mcg/kg IV

What an odd number

I don’t think that this is right, a quick google search shows completely different numbers.

58
Q

What is the potency of alfentanil?
What is its onset?

A
  • 20% as potent as fentanyl
  • Onset: 1.4 min (faster than all derivatives except remifentanil)
59
Q

What is the alfentanil induction dose?
What about laryngoscopy dose?
What about maintenance?

A
  • Induction: 150 - 300 mcg /kg IV
  • Laryngoscopy: 15 - 30 mcg/kg IV
  • Maintenance: 25 - 150 mcg/kg/hr with inhaled anesthetics
60
Q

What drug can cause acute dystonia when given to a Parkinson’s patient?

A

Alfentanil

61
Q

What receptor affinity does remifentanil have?
How potent is it?

A

μ opioid agonist that is equipotent to fentanyl

62
Q

What is remifentanil’s structure and why is it important?

A

Ester Structure = hydrolyzed by plasma & tissue esterases.

  • Rapid onset & recovery
  • Very titratable
  • No accumulation
63
Q

What drug was said to be a great choice for carotid procedures in lecture?

A

Remifentanil

64
Q

Answer the following characteristics of remifentanil below:
Clearance:
Peak effect:

A
  • Clearance: 3-L/min (8x faster than alfentanil)
  • Peak: 1.1 min (fastest fentanyl derivative)
65
Q

What is the induction dose of remifentanil?

A
  • 1 mcg/kg IV over 1 min
66
Q

What is the maintenance dosing of remifentanil?

A
  • 0.005 - 2 μg/kg/min IV
67
Q

How potent is hydromorphone?
What dose should be given?
What benefits does hydromorphone have over morphine?

A
  • 5x more potent than morphine
  • 0.5mg → 1-4 mg total
  • No histamine release & no active metabolites.
68
Q

Why is codeine not given IV?

A
  • Induced hypotension via histamine release.
69
Q

What is the dose of codeine for cough suppression?
Analgesia?

A
  • Cough: 15mg
  • Analgesia: 60mg (= about 5mg morphine)
70
Q

Which opioid is most cleared?

A
  • Remifentanil (3-4L/min)
71
Q

Which opioid(s) is/are the most protein bound?
Which is the least?

A
  • Sufentanil, alfentanil, & remifentanil
  • Least = morphine
72
Q

Which opioid is the highest percent non-ionized?

A
  • Alfentanil
73
Q

Morphine tends to relieve _____ type pain more than _____ type pain.

A

Dull: sharp