Pain, nociception and analgesia 3

Question 1

How do analgesics work?

Answer 1

They reduce peripheral nociception and sensitisation, they increase descending inhibition of nociception and reduce primary afferent nociceptive transmission and/or central sensitisation.

Question 2

What does NSAIDS stand for?

Answer 2

Non-steroidal anti-inflammatory drugs.

Question 3

What is used to treat mild pain?

Answer 3

Non-opiod NSAIDS, ibuprofen, paracetamol and aspirin.

Question 4

What is used to treat persisting moderate pain?

Answer 4

Low-potency opioids such as codeine, tramadol and buprenorphine.

Question 5

What is used to treat persisting severe pain?

Answer 5

High potency-opiods such as morphine, fentanyl and oxycodone.

Question 6

What are two opiate drugs?

Answer 6

Morphine and heroin.

Question 7

What are the differences between opiates and synthetic opioids?

Answer 7

Opiates are naturally derived from opium whereas synthetic opioids are drugs that bind to opioid receptors.

Question 8

Give examples of opiates.

Answer 8

Morphine and codeine.

Question 9

Give some examples of synthetic opioids.

Answer 9

Heroin, oxycodone, methadone, pethidine, fentanyl, buprenorphine, butorphanol.

Question 10

What are some unwanted effects of opioids?

Answer 10

Respiratory depression, pupil constriction, reduced gastrointestinal motility, sedation, physical dependence and catatonia.

Question 11

What receptors do strong opiates affect?

Answer 11

Mu, delta and kappa.

Question 12

What are some strong opiates?

Answer 12

Morphine, methadone and fentanyl.

Question 13

What are some weak opiates?

Answer 13

Codeine and buprenorphine.

Question 14

Why is tolerance an issue with opioid drugs?

Answer 14

Continued use requires increased doses for an equivalent effect.

Question 15

What are the different forms of administration of opiates?

Answer 15

Pills, intravenous injections, epidural, transfermal patch and lollipop.

Question 16

What opiates are taken in pills?

Answer 16

Morphine and codeine.

Question 17

What opiates are intravenously injected?

Answer 17

Morphine, diamorphine and fentanyl.

Question 18

What opiates are taken epidurally?

Answer 18

Fentanyl and pethidine

Question 19

What opiates can be taken using a transdermal patch?

Answer 19

Fentanyl.

Question 20

What opiates can be taken in a lollipop form?

Answer 20

Fentanyl.

Question 21

What are the properties of NSAIDS?

Answer 21

Analgesic, anti-inflammatory, anti-pyretic, all the effects are related to decreased prostaglandin synthesis.

Question 22

What are NSAIDs inhibitors of?

Answer 22

COX inhibitors.

Question 23

What are some of the disadvantages of NSAIDS?

Answer 23

Skin reactions, severe gastric irritation, nausea, vomiting, kidney disorders, cardiovascular effects, bronchospam.

Question 24

What supraspinal effects does morphine have?

Answer 24

Pre and postsynaptic reduction of GABA inhibition, increased excitatory output, increased activity of 5HT neurones, increased output from 5HT neurons and increased 5HT inhibition of second order neurons.

Question 25

What spinal analgesic effects does morphine have?

Answer 25

Decreased release of glutamate at primary afferent synapses, reduced action potential in primary afferent neurons and direct inhibition of second order afferent neurons.

Question 26

What peripheral analgesic effects does morphine have?

Answer 26

Decreased excitability of nociceptor terminals and decreased Ca2+ signalling in nociceptor terminals.

Question 27

What is the most widely used analgesic agent?

Answer 27

NSAIDs.

Question 28

Give some examples of NSAIDs.

Answer 28

Aspirin, ibuprofen, diclofenac, paracetamol.

Question 29

What pathway does NSAIDs affect?

Answer 29

They prevent prostaglandin being synthesised so the prostanoid receptor cannot be activated. This is due to the effect of COX being inhibited - cyclo-oxygenase1/2. The proastanoid receptor is involved in modulation at nociceptors.

Question 30

What effect do prostaglandins have?

Answer 30

They do not cause pain themselves but they sensitive bradykinins to increase nociception ?? i think ?? They block potassium efflux, making them more sensitive.

Question 31

Why do NSAIDs have a lot of adverse effects?

Answer 31

Both COX-1 and COX-2 are blocked.

Question 32

How can kidney disorders arise with NSAIDs?

Answer 32

Paracetamol overdose.

Question 33

What are some specific COX-2 inhibitors?

Answer 33

Rofecoxib and celecoxib.

Question 34

What are the benefits of specific COX-2 inhibitors?

Answer 34

There are less side effects, but there are cardiovascular complications.

Question 35

What are other analgesic approaches?

Answer 35

Tricyclic antidepressants, antiepileptic drugs, glutamate receptor blockers, neurokinin receptor blockers, cannabinoid receptor agonists, vanilloid receptor blockers.

Question 36

How do tricyclic antidepressants and antiepileptic drugs work to treat analgesia?

Answer 36

Na/Ca channel blockade - reduce primary afferent transmission.

Question 37

How do glutamate and neurokinin receptor blockers treat analgesia?

Answer 37

They block primary afferent transmission but have severe central side effects such as psychosis.

Question 38

How can cannabinoid receptor agonists be used for analgesia?

Answer 38

They have central and peripheral nociceptor effects that can be used for neuropathic pain such as MS.

Question 39

How do vanilloid receptor blockers act to treat analgesia?

Answer 39

ATP receptor blocker - they block the detection of peripheral noxious signals.