Opioid Analgesics 1 Flashcards Preview

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Flashcards in Opioid Analgesics 1 Deck (36)
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1

What are the general indications for opiates?

  • Moderate to severe dental pain - that cannot be managed effectively by NSAIDS
  • Those whom NSAIDS are contraindicated

2

What term is used to describe opiates, their antagonists, and the receptors stimulated by opioid drugs?

Opioids

3

How can opioids be classified?

  • Mechanism of action:
    • Agonists, partial agonists, mixed opioids (agonists/antagonists), antagonists
  • Chemical structure
  • Degree of efficacy that they produce

4

What are opioids mechanism of action?

  • They bind to receptors in both CNS and spinal cord
  • Produce altered perception of pain reaction

5

True or false: opioid receptors that mediate specific pharmacologic effects and adverse reactions are stimulated to varying degrees by individual opioids?

True

6

Where do opiates have their analgesic effect?

On the descending pain-modulating circuit - where there's a lot of endogenous opioid peptides

7

Where do systemic opiates produce analgesia?

At widely distributed sites throughout the CNS

8

In the pain modulatory system, what neurotransmitter is used?

Serotonin

9

What activates the descending pathway circuit of pain?

  • Noxious stimuli
  • Pain
  • Pyschological factors (placebo responders)
  • Opioids

10

The analgesia system is mediated by what 3 major componenets, where chemical mechanisms of opioid analgesics will take place?

  1. Periaquaductal grey matter (midbrain)
  2. Nucleus raphe magnus (medulla)
  3. Pain inhibitory neurons (dorsal horns of the spinal cord)

11

In addition to the opiate receptors - what other kind of receptors or connections are there in the descending pathways?

Noradrenergic and serotonergic receptors

12

Which projections are Serotonergic? And what are they highly sensitive to?

Projections from the periaqueductal gray matter (PAG) and RVM (rostroventral medulla)

Highly sensitive to morphine

13

What projections are noradrenergic? 

Projections from the dorsolateral pons - application of Norepinephrine to spinal cord blocks noxious stimuli in dorsal horn

14

What are the 3 groups of endogenous opioids?

  1. Endophins
  2. Enkephalins
  3. Dynorphins

15

What 3 different receptors do the endogenous opioids act through?

  1. Mu
  2. Delta
  3. Kappa

They are G protein-coupled receptors

16

Where are the endogenous opioid peptides produced?

In the pituitary gland and the hypothalamus

17

The endophrins cross-top in the limbic system, what is an indication of this?

When people get emotional when they take opioids

18

Which endogenous opioid is expressed in cells in the arcuate nucleus of the hypothalamus and in the brainstem, act via mu and influences appetite and sexual behavior?

Beta-endorphins

19

Which endogenous opioid is widely distributed throughout the brain and acts via mu and delta?

Enkephalins

20

Which endogenous opioid is found in the spinal cord and in many parts of the brain, including the hypothalamus, acts via kappa?

Dynorphins

21

What are endorphins derived from and what do they produce?

Derived from precursor molecules and produce opiate-like effects. 

22

Where are endorphins found?

In the gut (pancreatic islet cells), sympathetic nervous system, adrenal medullary chromaffin cells, CNS

MU receptors

23

Naturally occuring endorphins as well as opioid medications act via the mu receptors found in where?

The gastrointestinal tract - why you can get constipation from opioids (slows down the GI tract)

24

What are the first isolated compounds on enkephalins?

  • Leucine-enkephalin
  • Methionine-enkephalin

25

What do enkephalins act like?

Mimic opiate activity - weaker analgesics 

26

Enkephalins may be responsible for what?

Producing analgesia in placebo responders and acupuncture - act via mu and delta

27

What causes the side effects of opioid use (respiratory depression, pupil constriction, decrease body temp and gut motility)?

Opiate receptors found in tissues outside the CNS - that are NOT involved in analgesia

28

What kind of scan can you do to show opiate receptor activity in the brain?

PET - positron emission tomography

29

Recognition site of receptor is highly _________? And the analgesic action of opioid drugs is stereospecific, what isomer have biological activity?

Specific

Levo-isomers have biological activity

30

What are the 5 subtypes of opioid receptors?

  1. Mu
  2. Delta
  3. Kappa
  4. Epsilon
  5. Sigma (no longer classified as opioid receptor: responds to NMDA agonists - extas)