Euthanizing Agents

Question 1

What is euthanasia?

Answer 1

ending the life of an individual animal in a way that minimizes or eliminates pain and distress by rapid loss of consciousness followed by loss of vital body function (respiration, heartbeat, brain)

Question 2

What is the Panel on Euthanasia?

Answer 2

AVMA - convenes to evaluate methods and potential methods of euthanasia for the purpose of creating euthanasia guidelines for veterinarians by updating methods, techniques, and agents of euthanasia

Question 3

How has the Panel on Euthanasia widened their scope throughout the years?

Answer 3

• 1963: methods and recommendations applicable to dogs, cats, and other small mammals
• 1972, 1978: laboratory and food animals
• 1986: poikilothermic, aquatic, fur-bearing wildlife
• 1993: horses and wildlife

Question 4

What needs to be considered during euthanasia?

Answer 4

animal welfare and minimizing pain/distress

Question 5

What pre-euthanasia procedure is required to minimize pain and distress?

Answer 5

proper handling - also ensures the safety of the person performing the euthanasia

• amount of control is dependent on the species, breed, and size of the animal

Question 6

What behaviors after euthanasia administration should be communicated to the owner?

Answer 6

• vocalization
• agonal breaths
• muscle twitches
• failure of eyelids to close
• urination and defecation

Question 7

What are the 3 basic mechanisms of euthanasia?

Answer 7

1. direct depression of neurons vital for life functions
2. hypoxia
3. physical destruction of neurons and brain activity vital for life

Question 8

What 14 criteria where considered for evaluating euthanasia in the 2020 Panel of Euthanasia?

Answer 8

1. ability to induce loss of consciousness and death with minimum pain and distress
2. time required to induce loss of consciousness
3. reliability
4. personnel safety
5. irreversibility
6. compatibility with intended animal use and purpose
7. documented emotional effect on observers or operators
8. compatibility with subsequent evaluations, examinations, or use of tissue
9. drug availability and human abuse potential
10. compatibility with species, age, and health status
11. ability to maintain equipment in proper working order
12. safety for predators or scavengeers
13. legal requirements
14. environmental impacts of disposition of remains

Question 9

What is the caring-killing paradox? How can its effect be mitigated?

Answer 9

wanting to care for the animals you see, but needing to kill some of them for their own health

training personnel in the underlying justifications for euthanasia

Question 10

Why are most euthanasia agents not used in human medicine? What are some examples?

Answer 10

most have a narrow therapeutic index or excessive side effects —> commonly used in suicide attempts

• Acepromazine
• Xylazine
• T-61
• Barbiturates

Question 11

What is the preferred method for administering euthanasia solutions?

Answer 11

IV - most rapid, reliable

Question 12

What dose of anesthetics can be used as a euthanasia solution?

Answer 12

3-4x therapeutic dose

Question 13

What barbiturates is the most suitable IV euthanasia solution? What other 2 groups are used?

Answer 13

sodium pentobarbital

1. barbituric acid derivatives (oxybarbiturates) - sodium pentobarbitone, secobarbital
2. thiobarbiturates - thiopentone

Question 14

What are the 4 advantages to using barbiturates as euthanasia solutions?

Answer 14

1. speed
2. induce euthanasia smoothly
3. less expensive
4. FDA approved - readily available

Question 15

What is the mechanism of action of barbiturates? What happens at the high dose needed for euthanasia?

Answer 15

depresses CNS by interfering with sodium and potassium transport across the cell membranes, blocking postsynaptic transmission

bind directly to GABA, resulting in dose-dependent sedation, hypnosis, anesthesia, and respiratory depression

Question 16

Why is the disposal of barbiturates and carcasses containing it important?

Answer 16

avoid poisoning scavenging wildlife

Question 17

What are 7 disadvantages to used barbiturates as euthanasia solutions?

Answer 17

1. IV injection required
2. animal must be appropriately restrained
3. federal drug regulations require strict accounting and must be used under supervision of personnel registered with the US DEA
4. terminal gasp commonly occurs
5. animals may go through an excitatory phase
6. drug persists in remains
7. tissue artifacts (splenomegaly) may occur

Question 18

What is the preferred method of euthanasia for dogs, cats, horses, and other animals? What can be done if the preferred method of administration is not possible?

Answer 18

IV bartbituric acid derivative (sodium pentobarbitone, secobarbital)

intraperitoneal injection - if IV is distressful, dangeroud or difficult due to small patient size

Question 19

When in intracardiac injection of barbiturates allows for euthanasia?

Answer 19

if the animal is unconscious or anesthesized

Question 20

What is Tributane? What part of it has a strong narcotic effect? How does it act?

Answer 20

nonbarbiturate euthanasia agent containing Embutramide, chloroquine phosphate, and lidocaine

Embutramide (γ-hydroxybutyrate derivative)

causes respiratory depression in the CNS and induces sleep anesthesia

Question 21

What other organ system does Embutramide in Tributane affect? What 3 effects cause death?

Answer 21

CVS

1. hypotension
2. myocardial depression
3. ventricular dysrhythmias

Question 22

What is Chloroquine phosphate? Why was it added to Tributane?

Answer 22

antimalarial drug —> shortens the time from unconsciousness to death (profound CVS depressant)

Question 23

Why was Lidocaine added to Tributane?

Answer 23

reduces the pain associated with IV injection in cats

Question 24

How does Tributane cause death? How should it be administered? Why does it need to be used carefully in cats?

Answer 24

CNS depression, respiratory depression, and hypoxia = circulatory collapse

IV

(extralabel) - agonal breathing may occur

Question 25

What are 3 advantages to using Tributane?

Answer 25

1. rapid onset
2. induces anesthesia smoothly with minimal discomfort
3. schedule III status makes it simpler to obtain, store, and administer compared to sodium pentobarbital (schedule II)

Question 26

What are 5 disadvantages to using Tributane?

Answer 26

1. not currently being manufactured
2. IV injection
3. animal must be appropriately restrained
4. agonal breathing may occur
5. remains in animal’s remains

Question 27

What are the 3 agents found in T-61 (Tanax)? What are their mechanisms of action? In what 3 animals has use been described?

Answer 27

1. Embutramide - anesthetic, narcotic
2. Mebezonium iodide - nondepolarizing NMB
3. Tetracaine hydrochloride - local anesthetic

• dogs: IV
• amphibians: dorsal lymph sac
  – small birds: IM

Question 28

What are 2 advantages to using T-61 (Tanax)?

Answer 28

1. rapid onset (dogs, cats, horses, lab animals, birds, wildlife)
2. terminal (agonal) gasps not observed

Question 29

What 4 disadvantages are associated with T-61 (Tanax)?

Answer 29

1. not currently manufactured
2. slow IV injection required to avoid dysphoria prior to unconsciousness
3. animal must be appropriately restrained
4. secondary toxicosis may occur in animals that consume remains

Question 30

Making a decision regarding euthanasia:

Answer 30

Question 31

Evaluating morality:

Answer 31