analgesia

Question 1

what is an analgesic

Answer 1

an agent that alleviates pain without causing loss of consciousness

Question 2

what is a narcotic analgesic

Answer 2

aka an opioid analgesic which is a class of compounds that can act upon opioid receptors to block the preception of pain or modify the emotional response to pain

Question 3

what is a non-narcotic analgesia

Answer 3

a compound that achieves analgesia without acting upon opioid receptors

Question 4

what is an anti-inflammatory agent

Answer 4

a compound that supresses the inflammatory response

Question 5

what is a steroidal agent

Answer 5

chemically related to the steroid hormone cortisol, referred to as corticosteroids

Question 6

what is a nonsteroidal agent

Answer 6

NSAID

Question 7

what is an adjunctive agent

Answer 7

used to potentiate the effects of analgesics or manage associated issues

Question 8

where are opioid receptors located

Answer 8

everywhere

Question 9

what is the effect of opioids at the supraspinal level

Answer 9

indices euphoria and can alter the perception of pain by activating descending neural pathways that inhibit nociceptive transmission in the dorsal horn

Question 10

what are the potential disadvantages of opioid analgesics

Answer 10

addiction, sedation, constipation, hallucination

Question 11

what is the drug used to reverse opioid overdose

Answer 11

narcan (naloxone)

Question 12

how to NSAIDS work

Answer 12

they inhibit the COX enzymes to reduce prostaglandin synthesis and therefore reduce the inflammation which is causing pain

Question 13

cox 1 is responsible for synthesising prostaglandins for

Answer 13

homeostatic functions

Question 14

cox 2 is responsible for synthesising prostaglandins for

Answer 14

inflammation

Question 15

non selective cox inhibitors include

Answer 15

aspirin, ibuprofen, naproxen, diclofenac

Question 16

what are the adverse effects of nonselective nsaids

Answer 16

gi upset, skin rashes

overuse can lead to HTN and renal failure

Question 17

aspirin specific adverse effects include

Answer 17

directly toxic to the gastric mucosa, reyes syndrome, and tinnitus (associated with aspirin overdose)

Question 18

what are some common selective cox 2 inhibitors

Answer 18

celebrex, meloxicam

Question 19

what is the mechanism of paracetamol

Answer 19

poorly undersood but - it inhibits prostaglandin synthesis centrally rather than peripherally, indirectly interfering with COX activity by changing peroxide concentration

it also influences pain modulation pathways - serotonergic neurons, cannabinoid receptors

Question 20

in excess, paracetamol is

Answer 20

hepatotoxic

Question 21

who should be cautious when taking paracetamol

Answer 21

alcoholics - increased rate of conversion of paracetamol to its toxic metabolite
children
Low BMI

Question 22

how do local anaesthetics work

Answer 22

by blocking sodium channels - and decreasing the release of excitatory neurotransmitters, decreasing the ability of the action potential to cross the synapse - meaning no action potential is travelling up the neuron

Question 23

how do anti-epileptics (anticonvulsants) reduce neuropathic pain

Answer 23

by acting like GABA which is the major CNS inhibitory naurotransmitter, which downregulates pain by acting on the calcium channels (which decreases the ability of the action potential to cross the synapse)

Question 24

how do cannabinoids reduce pain

Answer 24

AEA and 2ag are synthesised in the post synaptic neuron, they they travel backwards towards the cb1 receptors and take out calcium channels (which decreases the ability of the action potential to cross the synapse)

Question 25

how do antidepressants work to reduce pain

Answer 25

serotonin and noradrenaline are inhibitory, an inhibitor to their reuptake will allow 5HT and NA to stay in the synaptic cleft for longer, keeping inhibitory neurotransmitters at a surplus over substance P, not allowing for the activation of the second order neuron if depression is present alongside pain, it can also help with the emotional perception of pain

Question 26

how to opioids work to reduce pain

Answer 26

periphery - opioid receptors are on free nerve endings - transduction is effected by blocking calcium channels on the presynaptic (first order) neuron and by causing a potassium efflux on the postsynaptic (second order) neuron dorsal horn - they will decrease transmission as well - by blocking calcium channels on the presynaptic (first order) neuron and by causing a potassium efflux on the postsynaptic (second order) neuron supraspinal brainstem (PAG) - causing increased descending pain modulation brain - decreasing pain perception

Question 27

why are opioids very effective at modulating pain

Answer 27

they act upon all levels (periphery, dorsal horn, midbrain, brain)

Question 28

why are opioids highly addictive

Answer 28

they produce eurphoria, the more you take the more opioid receptors you create + it decreases your ability to make your own endogenous opioids

Question 29

how do cortocoseroids work to reduce pain

Answer 29

by mimicking cortisol which is responsible for releasing sugar in times of stress and supressing the immune system. they act in the nucleus of the cell and dictate what the cell will synthesise, once it is at the DNA it tells the cell to synthesise lipocortin that will inhibit phospholipase A2 which tells the cell to downregulate inflammatory protein production, therefore having antiinflamatory affects, and affecting transduction and then also transmission

Question 30

what is the difference between an NSAID and corticosteroids

Answer 30

nsaids wil prevent cox producing prostaglandins, where as a SAID will directlt target the nucleus and change gene expression

Question 31

how does ketamine work to reduce pain

Answer 31

by acting as an antagonist on NMDA receptors and preventing glutamate from binding, which decreases pain as glutamate is excitatory to pain modulation in the CNS, stopping the pain signal from getting to where it was meant to go.