Opioid Analgesics Flashcards Preview

Pharmacology - Exam 2 > Opioid Analgesics > Flashcards

Flashcards in Opioid Analgesics Deck (67)
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1

define narcotic

"sleep-inducing"
better legal than medical term

2

define opiate

derived from opium
ie) morphine or codeine

3

define opioid

compound with pharmacology similar to morphine
ie) synthetic drugs or endogenous opioid ligands

4

define analgesic

pain-relieving

5

define endogenous opioids

naturally occurring opioids that mimic the actions of exogenous opiates in the brain and periphery

6

what three genes are endogenous opioids made from

POMC (pro-opio-melano-cortin gene)
Pro-enkephalin gene
Pro-dynorphin gene

7

what active opioid product does the POMC gene make

B-endorphin

8

what active opioid product does the pro-enkephalin gene make

met-enkephalin and leu-enkephalin

9

what active opioid product does the pro-dynorphin gene make

dynorphin-A (also dynorphin-B, neo-endorphins, and leu-enkephalin)

10

what endogenous opioid binds Mu opioid receptor

B-endorphin and enkephalins

11

what endogenous opioid binds Delta opioid receptor

mostly enkephalins and some B-endorphin

12

what endogenous opioid binds Kappa opioid receptor

dynorphin

13

where are the endogenous opioids working

at descending inhibitory pathway
have inhibitory effect on C pain fibers

14

what type of receptors are the opioid receptors? ionotropic? muscarinic/metabotropic?

muscarinic/metabotropic
ALL G-PROTEIN-COUPLED

15

of the three opioid receptors which is the major one and what are its effects

Mu opioid receptor
analgesia, respiratory depression, euphoria, dependence ie) drug addiction

16

what is an important non-opioid receptor

DM receptor
mediates antitussive effects (anti-cough)

17

therapeutic effects of opioids

analgesia
antitussive
antidiarrheal
(also mood enhancement and relief of acute pulmonary edema)

18

Of the three types of pain which does opioids not work well on

neuropathic pain

19

what is a problem with the antidiarrheal therapeutic effect of opioids

constipation

20

general effects of opioid analgesia

inc pain threshold (discriminative)
inc pain tolerance (affective/emotional)
selective for analgesia

21

what general effects of opioid analgesia is unique compared to local anesthetics

inc pain tolerance (local anesthetics don't do that, they just do the discriminative inc pain threshold) and selective for analgesia (local anesthetics are not selective, they affect other somatosensory modalities as well)

22

sites of action for opioid analgesia

opioid receptors at C fibers/ascending pain pathways and descending pain inhibitory pathways and cerebral cortex

23

major receptor of analgesic action

Mu opioid receptor with contribution from Delta opioid receptor

24

how does the analgesic action if opioids work at the ascending pathway

1) activate Mu opioid receptors on C fibers which blocks opening of Ca channels so NTs/sub P not released
2) activate Mu opioid receptors on spinothalamic neuron enhancing the opening of K+ channels leading to hyperpolarization
(slide 15)

25

what type of pain does opioid analgesia work on

best agains slow pain/C fiber pain (dull, burning, aching, constant) less effective against fast pain/A-delta fibers (sharp, intense, stinging intermittent pain)
**good against nociceptive and inflammatory pain
***bad against neuropathic pain

26

what is an example of neuropathic pain

postherpetic neuralgia resulting from shingles

27

how does the analgesic action if opioids work at the descending pain inhibitory pathway

Mu receptors activated in brain to activate descending pain inhibitory pathway that activates enkephalin containing interneurons that synapse onto the terminal end of C-fibers so Mu receptors on C-fibers activated which blocks the opening of Ca channels so NTs/sub P not released and enkephalins also work on spinothalamic neuron by opening K+ channels causing hyperpolarization
RESULT inhibition of pain ascending pathways
(slide 18)

28

pathway of the descending pain inhibitory pathway

descending serotonergic neurons from Raphe Nucleus
synapse onto enkephalin containing interneurons
synapse onto terminal end of C-fibers and have inhibitory effect on the release of NTs at this terminal end of C-fibers (C-fiber synapses onto spinothalamic neuron to thalamus)
RESULT is inhibition of ascending pain pathway

29

opioid use in anesthetic settings include

1) as premedication (act as sedative, anxiolytic, analgesic) prior to general anesthetic
2) intraoperatively as adjunct to general anesthetic or as primary general anesthetic
3) spinal anesthesia for thoracic or abdominal surgery or in labor

30

T/F antitussive effects are not mediated by opioid receptors

true