Analgesics

Question 1

What are the major classes of drugs used for acute pain?

Answer 1

NOPLAN 
NSAIDs
Opioids
Paracetamol 
Local anaesthetics
Alpha 2 agonists
NMDA agonists

Question 2

What are the 3 effects of NSAIDs?

Answer 2

Anti-pyrexic
Anti-inflammatory
Analgesia

Question 3

NSAIDs work by inhibiting COX. Is COX 1 or 2 ‘good’ or ‘bad’? Which one causes side effects when inhibited?

Answer 3

COX 1 - physiological, good. Side effects when inhibited

COX 2 - inflammatory, little side effects when inhibited

Question 4

What are some side effects of NSAIDs?

Answer 4

GI ulceration
Clotting
Photosensitisation
Hypersensitivity

Question 5

What are opioids used for? (2 effects)

Answer 5

Analgesia

Sedation

Question 6

Where are opioid receptors found?

Answer 6

Throughout body

In CNS - mainly dorsal horn of spinal cord

Question 7

What are the 2 ways of how opioids work?

Answer 7

Reduce excitatory neurotransmiter in nociceptors

Reduce neuronal response to nociceptive input

Question 8

What are the 3 main types of opioid? What do the 2 main types do?

Answer 8

Mu - analgesia and narcosis (loss of consciousness)
Kappa - sedation and visceral analgesia
Delta

Question 9

Give examples of opioids that are full mu agonists?

Answer 9

Methadone

Morphine

Question 10

Give an example of a partial mu agonist?

Answer 10

Buprenorphine

Question 11

What type of receptors does butorphanol effect?

Answer 11

Mu antagonist

Kappa agonist

Question 12

How do opioids tend to be administered?

Answer 12

Parenterally

Poor bioavailability orally

Question 13

What are the side effects of opioids?

Answer 13

Bradycardia
Respiratory depression
Reduced GI motility

Question 14

What are the effects of paracetamol?

Answer 14

Analgesia
Antipyrexia
(Not anti-inflammatory)

Question 15

Paracetamol MOA is unsure but could work via cannabinoid, serotonin receptors or COX 3 inhibition. How is paracetamol administered? Can it be given to all species?

Answer 15

IV or orally

NOT CATS - toxic, causes haemolysis

Question 16

What are the side effects of paracetamol?

Answer 16

Hepatoxicity

Hypotension (IV formula)

Question 17

What are the 4 effects of local anaesthetics?

Answer 17

Analgesia
Anti-inflammatory
Anti-arrhythmmic
Prokinetic (increases GI motility)

Question 18

How do local anaesthetics work?

Answer 18

Act on sodium channels in cell membrane

Stop propagation of AP in neurones

Question 19

What are the 2 main classes of local anaesthetics? Where are they metabolised? Are they long or short lasting?

Answer 19

Amides - liver metabolism longer acting

Esters - tissue metabolism, shorter acting

Question 20

Give an example of each of the 2 types of local anaesthetics

Answer 20

Amide - lidocaine

Ester - procaine

Question 21

What is pKA in terms of pharmacological properties? What does a high pKA mean?

Answer 21

Degree of ionisation
Affects ability to cross membrane (amount of active drug)
High pKA - great amount of ionised drug, faster onset

Question 22

How does protein binding of a drug effect duration?

Answer 22

Greater protein binding = longer duration

Question 23

How does vessel diameter affect drug duration?

Answer 23

Vasodilated drug = shorter duration

Question 24

What are the side effects of local anaesthetics?

Answer 24

Effects other nerves except nociceptors - loss of motor function
CNS toxicity
Cardiac toxicity

Question 25

What are the 2 effects of alpha 2 adrenoreceptor agonists?

Answer 25

``` Sedation Analgesia (shorter than sedation length) ```

Question 26

What are the 2 effects of NMDA antagonists?

Answer 26

Analgesia | Anaesthesia

Question 27

Give an example of a NMDA antagonist

Answer 27

Ketamine | Blocks NMDA receptor - anaesthesia

Question 28

How can ketamine be administered? Is it long are short acting?

Answer 28

IV, IM, SC, transmucosally | Short acting

Question 29

What are the side effects of ketamine?

Answer 29

Hypertonicity Excitement Myocardial depression Increased peripheral sympathetic tone

Question 30

For chronic pain, acute analgesic drugs are given along with others. Give examples of drugs additionally given

Answer 30

``` Gabepentin Amantadine Antidepressants Capsaicin Elk velvet antler ```