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Flashcards in Alpha 2 Agents Deck (17):
1

list the therapeutic benefits of Alpha 2 agonists:

sedation, analgesia, skeletal muscle relaxation

2

What are the major effects of xylazine on cadiovascular system?

Phase-1
activate peripheral alpha 2 receptors, rapid incrase in SVR, increases arterial BP

Phase 2
hypertension- baroreceptor mediated bradycardia
over time peripheral effects subside and the BP will return to normal

3

What are the major effects of xylazine on Gi/emesis

used in horses for tx colic associated pain
emesis frequently in cats; less often in dogs

4

What are the major effects of xylazine on renal?

increase in urine output onbserve transiently due to supression of ADH release centrally

5

What are the major effects of xylazine on uterine?

oxytocin like effect, dont give to cows in last trimester- abortion

6

What are the major effects of xylazine on respiratory?

minor hypoxia in cattle and sheep

activation of peripheral alpha-2 adrenoreceptors, leads to increase airway resistance

7

Adverse effects of xylazine:

synergistic actions with phenothiazines
additive effects w. CNS depressants
decrease plasma insulin levels (hyperglycemia/glycosuria)
RMTs are more sensitive to xylazine than dogs. horses, cat

8

What is the major clinical application of Yohimbine?

reversal agent for xylazine

adverse effect- CNS excitement, muscle tremors, salivation

9

What is the major clinical application of Atipamezole?

highly selective for reversal of medotomidine in dogs

10

What is the major clinical application of Tolazoline?

least selective antagonist

11

What drug is most selective for alpha 2 : alpha 1`

Medetomidine

12

What drug is least selective for alpha 2: alpha 1

Xylazine

13

What is the active enantiomer of medetomine?

dexmedetomine, the other is levomedetomidine`

14

Alpha 2 agonist mech of action

activation of presynaptic alpha 2 receptors in CNS/PNS
AND
post junctional alpha 2

results in decrease in sympathetic outflow

decrease in catecholamines

sedation, analgesia, and skeletal muscle relaxation

15

Where are the receptors that mediate sedation via alpha 2 agonists?

primarily in the locus coeruleus on the pons and lower brain stem- block NE release

16

What species is the most sensitive to alpha 2 agonism?

RMTs > cats/dogs > pigs

17

What is the mech of analgesia w/ regards to alpha 2 agonism?

pain modulation starts in the brain and SC
SC is site where nociceptive fibers synapse
both post/pre-synaptic inhibitory effects are responsible for the anti-nociceptive action
mediated by inhibition of inter neuronal transmission in SC