NSAIDs, NMBAs, Euthanasia

Question 1

Two peripheral effects of eicosanoids

Answer 1

vasodilation

Sensitization

Question 2

How does peripheral sensitization by eicosanoids contribute to pain?

Answer 2

increases sensitivity to messengers (bradykinin, histamine)

and increases sensitivity to mechanical touch and pressure

Question 3

Two effects of eicosanoids in the CNS?

Answer 3

increases activity of Ca channels

activates microglia

Question 4

How do NSAIDs produce analgesia?

Answer 4

inhibition of cyclo-oxygenase (COX)

Inhibition of lipoxygenase (LOX)

Question 5

Concerning inflammation, COX is responsible for production of which compounds

Answer 5

thromboxanes

prostaglandins

Question 6

3 homeostatic/housekeeping duties of COX

Answer 6

1) protection of gastric mucosa (dilates vessels to bring nutrients & promotes mucus production)
2) protection of kidneys (dilation of renal vessels)
3) coagulation of platelets (thromboxane important for clots)

Question 7

Which NSAIDs have COX-1 activity

Answer 7

ALL of them (some are just more selective for COX-2)

Question 8

3 beneficial actions of NSAIDs

Answer 8

1) anti-pyretic (C)
2) analgesic (P&C)
3) anti-inflammatory (P)

Question 9

3 primary side effects associated with NSAID use?

Answer 9

1) gastric irritation/ulceration (consider enterohepatic circulation)
2) renal damage/failure
3) prolonged clotting times

Question 10

3 instances when NSAIDs would be contraindicated?

Answer 10

1) if patient already has evidence of gastric ulceration
2) if patient has insufficient renal blood flow (meds, dehydration, hypotension, CHF)
3) if patient has clotting abnormalities

Question 11

labeled indication for Phenylbutazone

Answer 11

Horses–musculoskeletal pain

Question 12

labeled indication for Flunixin

Answer 12

Horses–muculoskeletal and visceral pain

Cattle– pyrexia, inflammation

Question 13

labeled indication for Carprofen

Answer 13

Dogs–post-op pain & osteoarthritis

Question 14

labeled indication for Meloxicam

Answer 14

dogs–Osteoarthritis

Cats–post-op pain

Question 15

labeled indication for Robenacoxib

Answer 15

Cats–surgical pain (up to 3 days)

Question 16

What is a neuromuscular blocking agent? How is it different from other muscle relaxants?

Answer 16

it blocks nerve conduction at NMJ to provide complete paralysis

Work peripherally, not centrally

Question 17

3 advantages of using NMBAs?

Answer 17

Immobility (for delicate surgeries where movement cannot occur)

Complete relaxation (penile relaxation)

Lower inhalant levels (good for patient’s with cardiovascular compromise)

Question 18

5 disadvantages for NMBAs

Answer 18

1) mechanical ventilation required (diaphragm paralyzed)
2) Monitoring (extra intense)
3) Uncertainty/Variable duration
4) Residual weakness
5) side effects (depends on drug)

Question 19

At what 4 locations does ACh function as a neurotransmitter?

Answer 19

1) nicotinic receptors
2) pre-ganglionic parasympathetic muscarinic receptors
3) post-ganglionic parasympathetic muscarinic receptors
4) pre-ganglionic sympathetic muscarinic receptors

Question 20

2 types of NMBAs?

Answer 20

Depolarizing

Non-depolarizing

Question 21

Describe how Depolarizing NMBAs work

Answer 21

mimic ACh, but aren’t as easily broken down so they work longer; lead to a persistent state of depolarization (rigid muscles) that is followed by relaxation after fatigue sets in

Question 22

Describe how non-depolarizing NMBAs work

Answer 22

bind ACh but have NO ACTIVITY (just blocks ACh binding)–>gradual muscle relaxation

also decreases vesicle fusion, which decreases presynaptic release of ACh

Question 23

A non-depolarizing NMBA used in vet med?

Answer 23

Atracurium

Question 24

How is atracurium eliminated and why is it beneficial (2 reasons)?

Answer 24

via hoffman degradation (temp & pH based)

elimination is independent of liver/kidney function & allows for a more predictable offset

Question 25

3 methods of NMBA reversal

Answer 25

elimination
indirect competitive antagonism
direct antagonist

Question 26

Describe how acetylcholinesterase inhibitors can be used to antagonize NMBAs

Answer 26

indirect antagonism

they allow build up of ACh in the synaptic cleft, which will eventually outcompete the NMBA for binding spots

Question 27

Predominant side effect seen when giving AChase inhibitor? How can it be prevented?

Answer 27

increase in muscarinic (vagal) stimulation (i.e. bradycardia)

can give anticholinergic (i.e. atropine, glycopyrrolate)

Question 28

What device is used to monitor paralysis with NMBAs?

Answer 28

peripheral nerve stimulator

Question 29

Which peripheral nerve stimulation pattern is used most often clinically?

Answer 29

Train of four (4 twitches 0.5sec apart)

compare first and last twitch to assess depth

Question 30

Where can a veterinarian find legal guidance for appropriate means of euthanasia?

Answer 30

State practice act (no guidelines in Al)

Question 31

3 classifications of euthanasia methods?

Answer 31

acceptable
acceptable with conditions
unacceptable

Question 32

What does it mean for a euthanasia method to be “acceptable”

Answer 32

it consistently produces humane death as a solo agent

Question 33

Name 7 ways death is confirmed after euthanasia

Answer 33

lack of pulse
lack of breathing
lack of corneal reflex
lack of response to toe pinch
inability to heart respiration and heart beat via stethoscope
graying of mucous membranes
rigor mortis

Question 34

the only acceptable solo sign to confirm death?

Answer 34

Rigor mortis

otherwise need to confirm at least 2

Question 35

3 causes of death following acceptable euthanasia

Answer 35

hypoxia (direct or indirect)
direct depression of neurons
physical disruption of brain

Question 36

When is intra-organ (i.e. cardiac) injection of injectable euthanasia acceptable? Exception?

Answer 36

when patient is anesthetized;

cats can have intrahepatic when no under anesthesia

Question 37

Most widely used injectable barbituate for euthanasia?

Answer 37

Sodium pentobarbital

Question 38

Why would a barbituate be combined with a cardio-active agent?

Answer 38

it makes it less likely to be abused, lowering it to a schedule III (from schedule II)

Question 39

General anesthesia and trained personnel allow for which drug to be an acceptable means of euthanasia?

Answer 39

potassium chloride

Question 40

Two acceptable forms of euthanasia for dogs and cats?

Answer 40

Barbiturates

Non-barbiturate anesthetic (propofol, ketamine/xylazine)

Question 41

Captive bolt is acceptable if combined with? (4)

Answer 41

adjunct agent:

1) pithing
2) exsanguination
3) potassium/magnesium salts
4) second shot

Question 42

What is the only “acceptable” method of euthanasia of equines

Answer 42

Barbiturates