Exam 1: General Opioids

Question 1

Opiates are:

Answer 1

Drugs derived from opium

Question 2

Opioids are:

Answer 2

Any substance that binds to opioid receptors and produces agonist effect

Question 3

Classes of opioids based on structure:

Answer 3

Phenanthrenes

Benzylisoquinolines

Question 4

Classes of opioids based on production:

Answer 4

Naturally occuring
Semisynthetic
Synthetic

Question 5

Groups of synthetic opioids:

Answer 5

Morphinan derivatives
Diphenyl derivatives
Benzomorphans
Phenylpiperidines

Question 6

Examples of morphinan derivatives:

Answer 6

Levorphenol

Butorphenol

Question 7

Example of dipheynl derivative:

Answer 7

Methadone

Question 8

Structure and examples of benzomorphans:

Answer 8

Morphine + benzene rings
Phenazocine
Pentazocine

Question 9

Examples of phenylpiperidines:

Answer 9

Meperidine
Fentanyl
Alfentanil
Sufentanil
Remifentanil

Question 10

Classes of opioids based on action at receptor:

Answer 10

Agonist
Partial agonist
Mixed agonist/antagonist
Antagonist

Question 11

Example of partial agonist:

Answer 11

Buprenorphine - regardless of dose, will not produce full mu receptor effects

Question 12

Example of mixed agonist/antagonist:

Answer 12

Nalbuphine - agonist at kappa, antagonist at mu

Question 13

Use of mixes agonist/antagonist:

Answer 13

Reverses respiratory depression while maintaining some analgesia

Question 14

Example of antagonist:

Answer 14

Naloxone

Question 15

Three endogenous opioid agonists:

Answer 15

Enkephalins
Endorphins
Dynorphins

Question 16

Mu receptor subtypes:

Answer 16

Mu-1
Mu-2
Mu-3 (immune-related)

Question 17

Location of mu receptors:

Answer 17

Brain and spinal cord, some in afferent neurons in periphery

Question 18

Three ways opioid receptor activation causes ↓ neuronal activity:

Answer 18

1. ↑ K+ conductance (hyperpolarization)
2. ↓ Ca2+ conductance (↓ neurotransmitter/sub P release)
3. ↓ cAMP

Question 19

Opioids are (weak/strong acid/base):

Answer 19

Weak bases (except alfentanil, remifentanyl)

Question 20

Effect of acidosis on opioid effect:

Answer 20

↑ ionization means less effective; higher doses will be needed

(but remember higher doses = ventilatory depression = worsening acidosis)

Question 21

Opioids must be in this condition to diffuse from blood to target tissue:

Answer 21

Unionized and unbound

Question 22

Alfentanil has rapid onset of action due to:

Answer 22

High % nonionized at physiologic pH

Question 23

Morphine has slow onset of action due to:

Answer 23

Only 23% nonionized at physiologic pH

Question 24

Effect of age on opioid PK/PD:

Answer 24

Neonates have ↓ elimination rate

Elderly are more sensitive

Question 25

Effect of weight on opioid PK/PD:

Answer 25

Base dose on IBW

Question 26

Effect of renal/hepatic failure on opioid PK/PD:

Answer 26

Can ↑ duration of action

Question 27

Spinal analgesia effects produced by:

Answer 27

Receptor activation in spinal cord (substantia gelatinosa) and dorsal root ganglion

Question 28

Supraspinal analgesia effects produced by:

Answer 28

Receptor activation in periaqueductal/periventricular gray and raphe nucleus

Question 29

CNS effects of opioids:

Answer 29

``` Analgesia (duh) Euphoria Sedation/drowsiness Miosis (pinpoint pupils) Nausea (CRTZ-related) Modest ↓ ICP, CBF ```

Question 30

Advantages of opioids in neuroanesthesia:

Answer 30

Hemodynamic stability | Cerebrovascular stability

Question 31

CV effects of opioids:

Answer 31

``` Generally no impairment in cardiac function Bradycardia (dose dep't) Vasodilation ↓ BP, CO Histamine release ```

Question 32

NMB with sympathomimetic effects and usefulness alongside opioids:

Answer 32

Pancuronium; SNS stimulation can offset opioid bradycardia

Question 33

Meperidine-specific CV effects:

Answer 33

Tachycardia | Myocardial depression

Question 34

Ventilatory effects of opioids:

Answer 34

Respiratory depression (dose dep't) ↓ chest wall compliance Constriction of pharyngeal, laryngeal muscles ↓ hypoxic ventilatory drive (need CO₂ to encourage breathing)

Question 35

Change in respiratory patterns with opioids:

Answer 35

Low dose: ↓ RR, ↑ TV | High dose: ↓ RR and TV... then apnea

Question 36

Ventilatory response curve after opioid administration:

Answer 36

Reduced and shifted to right

Question 37

Unique characteristic of fentanyl's peak effect:

Answer 37

Sequestration in lungs leads to two peaks

Question 38

Respiratory depression in fentanyl vs. morphine:

Answer 38

Respiratory depression from morphine is slower to peak but lasts longer

Question 39

Factors that increase opioid respiratory depression:

Answer 39

``` ↑ dose Intermittent bolusing (allows for stacking/tissue sequestration) Faster injection Synergy with other drugs ↓ clearance Age Alkalosis ```

Question 40

Skeletal muscle rigidity results from:

Answer 40

GABA inhibition | ↑ dopamine

Question 41

Renal/GI/liver effects of opioids:

Answer 41

``` ↑ peristalsis, tone of ureters (urgency) Blockade of catecholamine/cortisol release Sphincter of Oddi spasm Constipation Delayed gastric emptying ```

Question 42

Treatment for opioid-induced sphincter of Oddi spasm:

Answer 42

Glugacon 3mg

Question 43

Penetration into CSF with epidural administration depends on:

Answer 43

``` Lipid solubility (Very lipid soluble opioids will reach peak plasma as fast IV as intrathecal) ```

Question 44

Side effects of neuroaxial opioid administration:

Answer 44

Pruritis (most common) N/V Urinary retention Ventilatory depression