8: Mechanism of analgesia Flashcards Preview

Neurology Week 5 2018/19 > 8: Mechanism of analgesia > Flashcards

Flashcards in 8: Mechanism of analgesia Deck (52)
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1

Which type of analgesic drug reduces inflammatory pain by dampening down the inflammatory response?

NSAIDs

inhibit prostaglandin production by inhibiting COX1/2

2

How do NSAIDs work?

Cycloxygenase inhibitors

Reduce production of prostaglandins

3

Prostaglandins produce which three effects?

Inflammation

Pyrexia (fever)

Pain

4

Name five non-selective NSAIDs.

Aspirin

Ibuprofen

Diclofenac

Naproxen

Indomethacin

5

How can you tell that an NSAID is COX-2 specific?

It will be called something-coxib

6

What are some side effects of NSAIDs?

Peptic ulceration > GI bleeding

Renal toxicity

Cardiovascular problems (COX-2 only)

7

COX-2 inhibitors (-coxibs) aren't often used because they contribute to cardiovascular disease - how?

Prothrombotic

increase chance of DVT > PE, stroke

8

Which type of analgesic drug reduces pain by inhibiting nociceptive nerve transmission in the brainstem and posterior horn of the spinal cord?

Opioids

9

Which type of analgesic drug reduces pain by targetting ion channels involved in nerve damage and inflammation?

Anti-epileptics

10

Which type of analgesic drug works by inhibiting serotonin and noradrenaline reuptake?

Tricyclic anti-depressants

11

Which ion channel is blocked by many antiepileptic drugs e.g carbamazepine?

Na+

12

Describe the WHO analgesic ladder.

1. Non-opioid +/- adjuvant

2. Weak opioid +/- non-opioid +/- adjuvant

3. Strong opioid +/- non-opioid +/- adjuvant

13

Is paracetamol an NSAID?

Why (not)?

No

NSAIDs are anti-inflammatory, anti-pyrexial and analgesic - paracetamol isn't anti-inflammatory

14

What is the difference between pain and nociception?

Pain is the experience of suffering

Nociception is the nervous system's way of conveying pain signals to the brain

15

What is the Gate Control Theory?

Pain is transmitted by SMALL FIBRE sensory nerves

Mostly everything else is transmitted by LARGE FIBRE sensory nerves

if the large fibre nerves are transmitting impulses, inhibitory interneurons stop small fibre impulses (i.e pain impulses) from going any higher

i.e if you're bombarded with other sensory information, your perception of pain is reduced

16

In the Gate Control Theory, nerve impulses from large (Aα and Aß fibres) sensory fibres activate the ___ interneurone, stopping the transmission of pain signals.

inhibitory interneurone

17

Which types of nerve fibre are classed as large fibre sensory nerves?

A-alpha

A-beta

18

A-alpha and A-beta fibres are involved in dampening down nociceptive signals in the Gate Control Theory.

Which senses are these fibres responsible for?

A-alpha = proprioception

A-beta = skin mechanoreceptors

19

Which types of nerve fibre are classed as small fibre sensory nerves?

Which sensations do they control?

A-delta

C

Pain, temperature, itch

20

21

Which inhibitory neurotransmitter is involved in the Gate Control Theory?

GABA

Glycine

22

Which excitatory neurotransmitter is involved in the Gate Control Theory?

Glutamate

23

The Gate Control Theory is an example of (afferent / efferent) pain modulation.

afferent

ascending tracts, sensory

24

Pain modulation descending from the brain is known as (afferent / efferent) modulation.

efferent

25

Which area of the brainstem has an analgesic effect when stimulated?

Where specifically in the brainstem is it found?

Periaqueductal grey matter

Midbrain

26

The periaqueductal grey area of the midbrain is an efferent regulator of pain.

Apart from electrical stimulation, what activates it?

Opioids

27

What is the result of activation of the periaqueductal gray matter?

Nociceptive signals from the posterior horn are INHIBITED

i.e perception of pain is reduced

because Nucleus raphe magnus and Locus coeruleus are activated

28

What are the body's endogenous opioids called?

Enkephalins

29

When activated by electrical impulses or opioids, the periaqueductal gray area activates two other brain areas.

What are they called?

Nucleus raphe magnus

Locus coeruleus

30

Which chemicals are released by the nucleus raphe magnus?

What is the end result of this chemical release?

Serotonin (5-HT)

Enkephalins

inhibition of nociceptive transmission, analgesia