Quiz 1--Preanesthetics

Question 1

How does Atropine cause an initial decrease in HR?

Answer 1

stimulation of central vagal nucleus in medulla

Question 2

This anticholinergic is associated with decreases in GI and ruminal motility in horses and ruminants

Answer 2

Atropine

*can lead to ruminal stasis & colic (ileus)

Question 3

When comparing species sensitivities to atropine toxicity:

1) herbivores vs. carnivores
2) least resistant?
3) why are cats, rats, and rabbits more resistant?

Answer 3

1) herbivores are more resistant
2) pigs are least resistant
3) possess atropinase

Question 4

An anticholinergic that doesn’t penetrate the BBB as easily as atropine? Why doesn’t it penetrate as well?

Answer 4

Glycopyrrolate; larger molecular size

Question 5

Acepromazine has an effect on this neurotransmitter

Answer 5

Dopamine (antidopaminergic…increases turnover rate)

Question 6

Ace is involved in what receptor blockade? What does it lead to?

Answer 6

alpha-1; vasodilation/hypotension (anti-epinephrine)

Question 7

How can Ace cause hypothermia?

Answer 7

depletion of catecholamines from hypothalamus (thermoregulatory center) and peripheral vasodilation

Question 8

Name 3 important systemic effects of ace? (think heart, gut, cells)

Answer 8

antiemetic (good against opiate-induced vomiting)

antiarrhythmic (stabilizes myocardium)

Antihistaminic (acts on mast cells)

Question 9

T/F: though it lacks analgesic effects itself, ace can potentiate the analgesic effects of other drugs

Answer 9

True

Question 10

What drug should not be used to reverse droperidol-induced hypotension

Answer 10

epinephrine

Question 11

What two drugs combine to make innovarVet and what word is used to describe that drug? Use?

Answer 11

1) Droperidol & Fentanyl

Neuroleptanalgesic (tranquilizer & analgesic)

Vicious Dogs

Question 12

Describe the 3 MOA/effects of benzodiazepines

Answer 12

1) stimulate the benzodiazepine receptors and potentiate GABA–>increases Cl influx into cell to cause hyperpolarization
2) depresses limbic system (anxiolytic)
3) central muscle relaxation

Question 13

Purpose of propylene glycol vehicle for Dizepam?

Answer 13

increases solubility (Diazepam is usually not H2O soluble)

Question 14

Best anesthetic adjunct for critical patients due to its minimal cardiovascular effects?

Answer 14

diazepam

Question 15

Which two drugs combine to make telazol?

Answer 15

Zolazepam & Tiletamine

Question 16

Benzodiazepine antagonist

Answer 16

Flumazenil

Question 17

Sedatives are ______ receptor ______

Answer 17

alpha-2 receptor AGONISTS

Question 18

3 general anesthetic effects of the alpha-2 agonists

Answer 18

Sedation
Analgesia
Muscle relaxation

Question 19

How is the A2:A1 ratio related to potency?

Which drug has:

1) highest ratio
2) lowest ratio

Answer 19

the higher the ratio, the more potent the drug

1) Medetomidine/Dexmeditomidine
2) Xylazine

Question 20

Name 2 important systemic effects associated with Xylazine

Answer 20

1) increases urine output (inhibits ADH…esp. ruminants)

2) increases intrauterine contraction and pressure (premature parturition)

Question 21

Describe Xylazine’s impact on the cardiovascular system

Answer 21

biphasic effect on BP:
initial HYPERtension, followed by HYPOtension

Sensitizes myocardium (arrythmias likely!)

Question 22

How does Xylazine cause a biphase BP response?

Answer 22

Initial stimulation of post-synaptic A2 receptors

followed by stimulation of pre-synaptic A-2 receptors

Question 23

This drug can cause hypoxemia in sheep and calves

Answer 23

Xylazine

Question 24

Describe the species variations with xylazine:

1) ruminants vs. horses?
2) least sensitive?
3) list spp. from least to most sensitive

Answer 24

1) ruminants are 10X more sensitive than horses
2) pigs are least sensitive (need highest dose)
3) Pigs > horses > dogs > cats > ruminants

Question 25

It's important to let a horse calm down before giving ________

Answer 25

Xylazine (due to high circulating catecholamines after traveling...can lead to sudden death)

Question 26

Which a-2 receptor agonist is only approved for horses?

Answer 26

Detomidine

Question 27

Major difference between the IV and sublingual preparations of detomidine?

Answer 27

Sublingual preparation will not have analgesic effects

Question 28

Which drugs would be indicated for prevention of the oculocardiac reflex during surgery?

Answer 28

Anticholinergics (atropine, Glycopyrrolate)

Question 29

2 drugs that can treat Acepromazine-induced hypotension

Answer 29

Phenylephrine | Methoxamine

Question 30

Which drug should be used cautiously in horses during standing procedures and why?

Answer 30

Diazepam--can cause profound relaxation and recumbency

Question 31

Which benzodiazepine has the longest duration of action?

Answer 31

Zolazepam

Question 32

Which sedatives are associated with vomiting in cats/dogs?

Answer 32

Xylazine; Medetomidine

Question 33

3 contraindications for xylazine/sedatives in general

Answer 33

1) pregnancy 2) urethral obstruction 3) cardiac aberration

Question 34

This sedative is the best choice for diagnostic procedures (require deep sedation/immbolization but not general anesthesia)

Answer 34

Medetomidine

Question 35

Medetomidine + ________ can provide short-term anesthesia in small animals and zoo/wildlife spp.

Answer 35

Ketamine

Question 36

A unique feature of this sedative is its use as a CRI

Answer 36

Dexmeditomidine

Question 37

A benefit of Romifidine (compared to xylazine & meditomidine)

Answer 37

causes less ataxia and sedation (horses can maintain higher head position) *good for dentals!

Question 38

Name 3 alpha-2 antagonists

Answer 38

Yohimbine Tolazoline Atipamezole

Question 39

Concerning the 3 a-2 antagonists, which: 1) has the greatest selectivity for a-2 2) has least selectivity for a-2

Answer 39

1) Atipamezole | 2) Tolazoline

Question 40

Two major side effects associated with Tolazoline?

Answer 40

``` Tachycardia GI distress (stimulates GI musculature) ```

Question 41

Severe toxicity of llamas and camels is associated with which a2 antagonist?

Answer 41

Tolazoline *Llamas and camelids are sensitive to Tolazoline

Question 42

Best drug choice if you're trying to: 1) reverse sedation (CNS effects) 2) reverse ruminal hypomotility

Answer 42

1) atipamezole | 2) Yohimbine & Tolazoline

Question 43

Which pre-anesthetic is useful for large animals when other sedatives/tranquilzers fail?

Answer 43

Chloral Hydrate

Question 44

This sedative is characterized by "latent action" (name it and describe why)

Answer 44

Chloral Hydrate it has to form an active metabolite (Trichloroethanol) **it's active metabolite exerts the anesthetic effects

Question 45

What benefit does magnesium sulfate offer when combined with Chloral hydrate?

Answer 45

enhances muscle relaxation (has neuromuscular blocking effects)