pharmacology of pain management

Question 1

what are the two types of pain?

Answer 1

nociceptive and neuropathic

Question 2

what is nociceptive pain

Answer 2

caused by tissue damage, generally time-linted

Question 3

what is neuropathic pain

Answer 3

caused by damage to neurones, tends to be chronic

Question 4

nociceptive pain is relieved by?

Answer 4

analgesics specifically NSAIDs and opioids

Question 5

what does NSAIDs stand for

Answer 5

non-steroidal anti-inflammatory drugs

Question 6

what are the four main properties of NSAIDs

Answer 6

1. anti-inflammation
2. anti-pyretic: reduces fever
3. analgesic: rapid pain relief via CNS and PNS
4. anti-coagulant

Question 7

how do NSAIDs work

Answer 7

effects are achieved by preventing the breakdown of arachidonic acid by inhibiting cyclo-oxygenase (COX enzymes). This decreases the production of prostaglandins and thromboxane. By preventing prostaglandin production the NSAID reduces neuronal firing decreasing pain sensation

Question 8

what are the characteristics of opioids

Answer 8

1. analgesia
2. anaesthesia
3. antitussive effects: decrease cough reflex
4. antidiarrheal effects

Question 9

how do opioids reduce neuronal activity in the CNS and PNS

Answer 9

Opioids reduce neuronal activity in the CNS and PNS by binding to the opioid receptors:

1. Decreased opening of voltage-dependent Ca2+ channels
2. Increased K+ outflow
3. Decreased Ca2+ is release from intracellular stores
4. Decreased exocytosis of transmitter vesicles

Question 10

paracetamol is similar to what type of analgesic

Answer 10

NSAIDs

Question 11

what are the properties of paracetamol

Answer 11

• very good analgesic
• very good antipyretic

has very little anti-inflammatory effects

Question 12

which type of pain is harder to treat

Answer 12

neuropathic

Question 13

what are the types of drugs that treat neuropathic pain

Answer 13

1. tri-cyclic antidepressants

2. antiepileptics

Question 14

how do tri-cyclic antidepressants work

Answer 14

block the reuptake of both 5HT (serotonin) and noradrenaline.

• By increasing 5HT and NA they increase the activity in the descending pathways which blocks transmission. They can act in a positive way.
• Block adrenoreceptors, histamine receptors and muscarinic receptors. Antihistamines can block inflammatory responses and blocking adrenoreceptors helps with pain management

Question 15

how do antiepileptics work

Answer 15

Act to reduce the hyperactivity in the neurones that is associated with neuropathic pain.

1. Gabapentin: block voltage dependent calcium channels which would decrease hyperactivity
2. Carbamazepine: can block voltage dependent sodium channels which also decrease neuronal activity

Question 16

how do anaesthetics work

Answer 16

enter the cell through the membrane in an unionised form and become ionised in the intracellular space. In this form, it can block the inside of the Na+ channel

Question 17

what type of anaesthesia is an epidural

Answer 17

local

Question 18

how does epidural anaesthesia work

Answer 18

It reduces pain but still allows the mother to respond to changes in pressure and be able to push

Question 19

which type of neurone is more sensitive to the effects of local anaethetics

Answer 19

sensory

Question 20

what are side effects of NSAIDs

Answer 20

GI upset 
heartburn 
nausea
diarrhoea 
bleeding

Question 21

what are the side effects of opioids

Answer 21

• dependency
• constipation
• vomit and nausea
• depression
• respiratory depression

Question 22

how can opioid side effects be reversed

Answer 22

opioid antagonist such as naloxone

Question 23

what is a tension headache and where does it affect

Answer 23

associated with physical and mental tension, normally bilateral affecting both sides of the head and often felt at the back of the head

Question 24

what is a sinus headache and where does it affect

Answer 24

result of inflammation of blocking leading to an increased pressure being felt over the location of the sinuses.

Question 25

what is a migraine and where does it affect

Answer 25

painful and debilitating form of headache. Migraines are often associated with gastrointestinal upset, and vomiting. normally unilateral affecting most of the head on one side with a focal point generally located behind the eye

Question 26

what are cluster headaches and where are they located

Answer 26

rapid onset and strong severity that are associated with changes in the autonomic nervous system. They are called clusters as they may have a number of headaches occurring in close succession.

Question 27

cluster headaches are associated with

Answer 27

increased excretions, running eyes and nose as a result of the involvement of CNV trigeminal nerve

Question 28

what are medical overuse headaches

Answer 28

taking too many painkillers may lead to onset of medication overuse headaches