Sedatives

Question 1

Three alpha-2 adrenergic agonists

Answer 1

Xylazine (longest)
Dexmedetomidine
Detomidine (shortest)

Question 2

Which of the three main a2 sedatives is used in small animal?

Answer 2

dexmedetomidine

Question 3

Which two a2 sedatives are available as oral gels?

Answer 3

dexmedetomidine and detomidine

Question 4

Why is xylazine “special?”

Answer 4

least expensive and the least a2 specific

Question 5

xylazine in ruminants vs horses

Answer 5

ruminants are TEN TIMES more sensitive

Question 6

a1

Answer 6

vasoconstriction of blood vessels; also possible agitation and increased locomotor activity (though uncommon)

Question 7

a2

Answer 7

effects on brain and spinal cord to cause sedation, analgesia, anxiolysis

Question 8

a2:a1 ratio

Answer 8

Question 9

Which a2 drug doesn’t have CV effects?

Answer 9

trick question, none of them - they all have marked cardiovascular effects

Question 10

Cardiovascular Effects of a2 Adrenergic Agonists on the Cardiovascular System (3)

Answer 10

Vasoconstriction
Bradycardia
Decreased cardiac output

Question 11

Biphasic Response of a2 Sedatives

Answer 11

Phase 1 = increase BP and bradycardia (d/t vasoconstriction from a1) (peripheral effects)
Phase 2 = return to normal/decrease BP as drug dissociates (central effects)

Question 12

Why do both phases of a2 result in bradycardia?

Answer 12

Phase 1 = baroreflex
Phase 2 = decrease in sympathetic outflow

Question 13

2nd degree AV block

Answer 13

can be seen in a2 administration
dominant parasympathetic tone

Question 14

Cardiac Output Equation

Answer 14

CO = SV x HR

Question 15

Should you use a2 adrenergic agonists in high risk patients - why or why not?

Answer 15

NO, only for healthy patients

SIGNIFICANT decrease in cardiac output so perfusion to organs is reduced

Question 16

Tidal Volume and a2

Answer 16

TV increases with a2 alone; with other drugs it is a depressant and causes upper airway relaxation

Question 17

PIMS (pulmonary intravascular macrophages)

Answer 17

unique cell in ruminant lungs activated by a2 agonists, leading to irreversible pulmonary edema and hypoxemia

Question 18

Effect of a2 on Urine?

Answer 18

MASSIVELY increases urine production (so caution with urinary blockages)

Question 19

Can you use a2 in diabetic patients?

Answer 19

No, it causes hyperglycemia

Question 20

a2 and GI system

Answer 20

decreases motility and inc. smooth muscle relaxation (good for colic pain in horses)

Question 21

atipamezole

Answer 21

reversal agent for a2 agonists that MUST be given IM!!!!

Question 22

acepromazine

Answer 22

dopamine antagonist, no analgesia

cannot be used in allergy testing

Question 23

Splenic Sponge Effect of Acepromazine

Answer 23

PCV with decrease by 30-30% due to splenic sequestration

Question 24

Azaperone (oink)

Answer 24

pig acepromazine (mainly used in Europe or for elephants)

Question 25

Can diazepam be mixed with other drugs? Why or why not?

Answer 25

no - it’s lipid soluble so it is very oily (use midazolam if wanting to mix in a benzo)

Question 26

Benzodiazepine MOA

Answer 26

GABAa agonist

Question 27

Flumenazil

Answer 27

benzodiazepine antagonist

Question 28

Trazadone MOA

Answer 28

serotonin receptor antagonist and re-uptake inhibitor (SARI)

Question 29

yohimbine

Answer 29

an a2 reversal that isn’t used much anymore