Choosing Appropriate Premedication & Sedation

Question 1

what are aims of premedication (5)

Answer 1

1. to produce a calming effect, or sedation
2. to provide analgesia
3. to reduce doses of other agents required
4. to “smooth” induction and recovery
5. to counteract unwanted effects of other anesthetic drugs

Question 2

what are the drug groups used for pre-meds and sedatives (8)

Answer 2

1. phenothiazines: acepromazine
2. alpha2 agonists: medetomidine, dexmedetomidine, xylazine, detomidine, romifidine
3. opioids
4. benzodiazepines
5. anti-cholinergics
6. induction agents: ketamine, alfaxalone
7. anti-histamines?
8. steroids/NSAIDs?

Question 3

what are the effects of anticholinergics and what are examples

Answer 3

block effect of acetyl choline at receptors, block parasympathetic effects

ex. atropine, glycopyrrolate

Question 4

what are the effects of anti-cholinergics (5)

Answer 4

1. reduce salivation & resp secretions
2. pupilary dilation
3. increase HR
4. increase oxygen consumption
5. decreased gut motility

Question 5

are anti-cholinergics commonly used

Answer 5

no

Question 6

what is synergy

Answer 6

when two drugs are combined get greater effect

Question 7

what is neuroleptanalgesia

Answer 7

administration of a tranquilizing drug and an analgesic especially for relief of surgical pain

Question 8

what is an example of neuroleptanalgesia

Answer 8

acepromazine + buprenorphine

fentanyl + fluanisone

Question 9

what are common drug combinations used

Answer 9

medetomidine + butorphanol (dogs)

dexmedetomidine + methadone (horses)

Question 10

what are combs used with alfaxalone

Answer 10

+ butorphanol

+ midazolam

Question 11

when is alfaxalone useful

Answer 11

in sick and not easy to handle cats

Question 12

what are the combos of ketamine used

Answer 12

midazolam + ketamine IM (cats)

alpha 2 agonist + opioids + ketamine (triple combo)

Question 13

what are possible routes of administration

Answer 13

Question 14

how do sedatives influence recovery

Answer 14

residual sedative effects from premeds will influence recovery

ACP - long effect

Question 15

how do you decide what sedation is needed

Answer 15

1. temperament
2. procedure - duration, immobility, what degree of responsiveness acceptable?

Question 16

how would you pre med a 9 month old SBT for castration who is very lively

Answer 16

IM route (difficult to restrain for IV)

medetomidine + ketamine or

ACP + an opioid buprenorphine for a castration

butorphanol not as much analgesia

Question 17

how would you premed a CKCS with a grade IV/VI systolic murmur, mitral valve disease prior to a patella luxation

Answer 17

IV route good

opioid: want a full agonist (methadone)

probably don’t need a sedative because its a quite dog, but could use medetomidine but it can cause vasoconstriction

ACP can cause vasodilation

Question 18

how would you sedate an aggressive cat for neutering, impossible to do clinical exam

Answer 18

IM route

medetomidine + butoprhanol + ketamine (triple drip)

Question 19

how would you premed a 14 year old SBT X with renal disease, epistaxis for imaging of head/investigation of epitaxis

Answer 19

butorphanol –> good for a quite animal and don’t need analgesia for this procedure

ACP: may decrease BP

a2 agonists: probably don’t need in a quite animal, and vasoconstriction can effect renal perfusion

benzodiazepam doesn’t produce sedation on its own