Pain Management In Food Animals

Question 1

What is the pathway of pain from stimuli to perception?

Answer 1

Noxious stimuli —> peripheral nociceptors —> transduction spinothalamic tract —> dorsal horn of spinal cord —> modification of impulse by CNS neurotransmitters —> perception and emotion of pain

Question 2

What are behavioural signs of pain in food animals?

Answer 2

Vocalizing/grunting 
Tail swishing 
Limping 
Bruxism 
Laying down 
Depression 
Lowering the head 
Rigid posture 
Kicking/stomping 
Excessive licking area 
Reluctance to move 
Inappetence

Question 3

What are physiological signs of pain?

Answer 3

Increased respiration
Increased HR
Increased body temp
Increased pupil size

These can also be a normal stress response

Question 4

How do local anesthetics provide analgesia?

Answer 4

Block sodium channels in nerve cells
Inhibit conduction and transmission of signals

Infected tissue = lower pH = reduced effect

Question 5

What two local analgesics can be used in food animals?

Answer 5

Lidocaine: 2-5mins onset, duration 90+ mins

Bupivacaine: 20-30min onset, 5-8hr duration

Question 6

T/F: analgesia of the lower limb/foot only lasts for as long as the tourniquet is on

Answer 6

True

Question 7

What is the MOA of NSAIDS?

Answer 7

Inhibits cyclooxygenase isoenzyems (COX), lowering prostaglandin production from arachidonic acid

PG contributes to inflammation via vasodilation and inflammatory cell recruitment

Excess PG in the spinal cord causes central sensitization and chronic pain

Question 8

____________ is the main driver of PG and COX2 up regulation

Answer 8

COX 2

Question 9

Prolonged block of COX 1 can lead to what side effects?

Answer 9

Renal and GI issues

Question 10

How are NSIADS distributed, metabolized, and excreted?

Answer 10

High plasma protein binding and low volume of distribution

Met if liver

Ex by kidney

Question 11

What is the only NSAID approved for use in the US for cattle and swine?

Answer 11

Flunixin megumine

Question 12

What is Banamine labeled for?

Answer 12

Fever/inflammation associated with resp disease and mastitis and endotoxemia

Question 13

What NSIAD is approved in EU and Canada as an adjunct treatment for fever, pain, and inflammation associated with mastitis?

Answer 13

Ketoprofen

Also for painful conditions of bones and joints

Question 14

What NSIAD is approved in EU and Canada as an adjunct therapy for acute resp dz, diarrhea, and acute mastitis or as an analgesic post dehorning?

Answer 14

Meloxicam

Question 15

T/F: use of opioids in food animals is ELDU

Answer 15

True

Question 16

What is the most commonly used opioid i vent med because it has fewer adverse effects?

Answer 16

Butorphanol

Question 17

MOA if xylazine?

Answer 17

A2 agonists — reduce norepi release from pre-synaptic nerves in brainstem and spinal cord

—> block afferent nerve pathway

Question 18

Adverse affects assoicated with A2 agonists?

Answer 18

Decreased resp rate 
Lower GI motility 
Decreased CO 
Uterine contractions
Relaxation of cardiac sphincter