Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2a- pharmacology lectures > pain and opioid pharmacology > Flashcards

pain and opioid pharmacology Flashcards

1
Q

name a naturally occurring opioid

A

from the opium poppy ->

morphine
codeine (weaker)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

name a synthesised opioid

A

fentanyl - made to have faster onset time

heroin aka. diamorphine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the antidote to opioids?

A

naloxone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are routes of administration for opioids ?

A

oral - need x2 as IV (50% bioavaibabilty)
IM
IV -fastest, can use patient controlled analgesia (patient presses button for more from IV)
lollipops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what class drugs are opioids?

A

class A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how do opioids reduce pain ?

A

they use the existing pain modulation system

inhibit the release of pain transmitters at spinal cord and midbrain – and modulate pain perception in higher centers – euphoria – changes the emotional perception of pain

Block it with release of endorphins and enkephalins (pleasurable. euphoric hormones)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which pain pathway do opioids act on?

A

Descending inhibition of pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

are opioids designed for short term or long term pain relief?

A

designed for short term pain relief

Sustained activation leads to tolerance and addiction through Downregulation of receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how soon does opioid withdraw start?

A

within 24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why are there some side effects of opioids, not to do with pain relief ?

A

Opioid receptors exist outside the pain system e.g. digestive tract, respiratory control centre

we tend to administer them systemically eg. IV therefore they affect the whole body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

list examples of side effects of opioids

A

Respiratory depression
Sedation
Nausea and vomiting
Constipation
Itching
Immune suppression
Endocrine effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how is respiratory depression caused by morphine?

A

Morphine is metabolized to morphine 6 glucuronide which is more potent than morphine and is renally excreted.

With normal renal function this is cleared quickly

In renal failure it will build up and may cause respiratory depression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

advice for prescribing opioids

A

*Before prescribing opioids, discuss with the patient the risks and features of tolerance, dependence, and addiction - use short term courses

Agree a treatment strategy and plan for end of treatment

Warnings have been added to the drug labels and packaging of opioids to support patient awareness

At the end of treatment, taper dosage slowly to reduce the risk of withdrawal effects - may take weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why does different dosages of codeine affect people differently?

A

Codeine is a prodrug - it needs to be metabolised by cytochrome CYP2D6 into morphine to work

CYP2D6 activity varies in patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

should you prescribe codeine for non-cancerous pain?

explain why

A

no - it loses affect quickly (tolerance builds to pain relief) and is very addictive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the WHO pain ladder?

A

simplistic way to rate pain intensity .

There are 3 rungs to the ladder, corresponding to increasing pain intensity.

The clinician prescribes medications as pain worsens, moving from one rung to the next.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the 3 rungs to the pain ladder?

A

1) anti-inflammatory agents, for mild pain

2) weak opioids, for mild - moderate pain

3) strong opioids for moderate to severe pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

define pain

A

an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are current opinions on the WHO pain ladder?

A

nowadays seen as outdated, hasn’t been updated eg. does not include fixed dose combination analgesics in step 2.

need to add a 4th sept for very severe pain

20
Q

general pain pathway - how many neurones are involved?

A

3 orders of neurones

these carry action potentials signalling pain

21
Q

what do first order neurones do in the pain pathway?

A

reaches from peripherals (detects pain) to spinal cord (cells bodies within the dorsal root ganglion.)

22
Q

what do 2nd order neurones do in the pain pathway?

A

decussates to contralateral cord and ascends in the spinothalamic tract to the ventral posterolateral nucleus of the thalamus

23
Q

what do 3rd order neurones do in the pain pathway?

A

thalamus to midbrain & higher cortical centres (primary sensory cortex)

24
Q

what are the specialist receptors that 1st order neurones have to detect pain?

A

Nociceptors

found at free nerve endings of primary afferent neurones

25
Q

what are the different types of Nociceptors?

A

mechanical - distention and pressure

chemical

thermal

polymodal - chemical, mechanical and thermal

26
Q

opioid receptors - how do they work and produce analgesia

A

G protein-coupled receptors

their activation leads to a reduction in neurotransmitter release and cell hyperpolarisation,

reducing cell excitability.

27
Q

what are the 3 types of endogenous opioids (body already contains them)

exogenous = morphine etc.

A

Β-endorphins
Dynorphins
Enkephalins

28
Q

define first pass metabolism

A

rapid uptake and metabolism of an agent into inactive compounds by the liver, immediately after enteric absorption and before it reaches the systemic circulation

i.e. concentration of the drug is greatly reduced before it reaches systemic circulation.

29
Q

explain why oral morphine has a bioavailability of 50%

ie. the oral dose is 10mg, the IM dose is 5mg

A

if given orally, is has to undergo first pass metabolism

it is metabolised by the intestine and liver before reaching try systemic circulation

30
Q

if a patient has renal impairment, any morphine should be given in lower doses and in longer intervals

why is this the case?

A

Morphine is metabolised in the liver to morphine 6 glucuronide which is more potent than morphine.

morphine 6 glucuronide is then excreted by the kidneys

if a patient has renal failure it will not be as readily excreted. risk of the potent morphine building up therefore prescribe them lower doses

31
Q

define acute pain

A

pain for less than 12 weeks

32
Q

define chronic pain

A

continuous over 12 weeks, the pain persists beyond the tissue healing time

33
Q

what is the difference between somatic and visceral pain ?

A

Somatic = pain of the muscles, bones, soft tissues
Visceral = pain of the internal organs

34
Q

what is thalamic pain

A

burning pain

caused by damage to thalamus in stroke

35
Q

what is neuropathic pain

A

damage to nerves causing spontaneous pain (shooting,burning,pins and needles feeling)

or evoked pain by stimulus that shouldnt produce pain normally eg. touching something cold

36
Q

what is psychosomatic pain

A

pain lacking a medical explanation eg. caused by stress

37
Q

what is referred pain

A

when the pain you feel in one part of your body is actually caused by pain or injury in another part of your body. Eg. an injured pancreas could be causing pain in your back,

38
Q

what is Illusionary pain

A

an illusion, disconnected from reality

39
Q

define hyperalgesia

A

enhanced sensation of pain at normal threshold stimulation

40
Q

Define allodynia

A

pain experienced in response to a stimulus that was previously not painful.

41
Q

what is the sensory pathway responsible for carrying pain and temperature information from the skin to the thalamus and primary sensory cortex

A

the spinothalamic tract

42
Q

where does the spinothalamic tract decussate

A

2nd order neurone crosses to contralateral spinal cord

43
Q

are the neurones that carry pain signals to the brain afferent or efferent

A

afferent sensory neurones

44
Q

what type of primary afferent fibres tend to carry the sensory information to the spinal cord and why

A

Alpha-delta fibres

they are myelinated therefore fast conduction

45
Q

what type of primary afferent fibre tends to carry secondary pain information and why

A

C fibres

slower conduction as unmyelinated

2a- pharmacology lectures (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions