Premedication and Sedation

Question 1

Which pre-med drugs can be given on the tongue (buccal method)?

Answer 1

Medetomidine, ketamine and buprenorphine are well absorbed.

Question 2

Give examples of drugs which are Phenothiazines (tranquilizers)

Answer 2

Acepromazine
Chlorpromazine
Prochloperizine

Question 3

What class of drug is Acepromazine and what is its manufacturing name?

Answer 3

Phenothiazine (tranquilizer). ACP, Atravet or Sedalin Gel

Question 4

What class of drug is Chlorpromazine and what is its manufacturing name?

Answer 4

Phenothiazine (tranquilizer). Largactil.

Question 5

What class of drug is Prochloperizine and what is its manufacturing name?

Answer 5

Phenothiazine (tranquilizer). Stemetil.

Question 6

On which receptors do Phenothiazines bring about their effects?

Answer 6

alpha1 and alpha2, dopamine, 5HT, histamine and muscarinic.

Question 7

How do Phenothiazines, such as ACP, bring about their sedative effects?

Answer 7

Dopamine antagonist, also act on 5HT receptor and have central anti-cholinergic effects.

Question 8

What are the disadvantages of Phenothiazines?

Answer 8

Cause impaired thermoregulation

Question 9

What other effects do Phenothiazines have and through which receptors?

Answer 9

anti-emetic- through chemotactic trigger zone dompamine inhibition
Anti-histimine- block H1 receptors
Vasodilation- cause tachycardia, hypotension, hypothermia, decreased haematocrit, priprism

Question 10

In which patients should Phenothiazines such as ACP not be used?

Answer 10

Epileptics, anaemics

Question 11

How strong is the sedation with Phenothiazines?

Answer 11

mild but long lasting, synergistic with opiods and alpha2 agonists

Question 12

How are phenothiazines metabolised?

Answer 12

Mostly hepatic- careful of sight hounds which are deficient in P450.

Question 13

What drug should you never use a Phenothiazine such as ACP with?

Answer 13

Should not sure adrenaline to reverse hypotension- causes even more severe hypotension. Use noradrenaline instead.

Question 14

What other drug interactions do Phenothiazines have?

Answer 14

synergistic with other sedatives, organophosphate anthelmintics, propanolol, procaine, quinidine, phenytoin

Question 15

What doses of Phenothiazines should be used in the dog, cat and horse?

Answer 15

0.005-0.1mg/kg (oral dose should be 10 times systemic)

not sued in sheep cattle and pigs

Question 16

What breeds are sensitive to phenothiazines?

Answer 16

sight hounds, boxers and brachycephalics

Question 17

Name some alpha-2 agonist drugs

Answer 17

xylazine, detomidine, metedomidine, dexmedetomidine, romidine

Question 18

What is the band name for Xylazine and how does it work?

Answer 18

Rompun. presynaptic alpha2 receptor agonist. decreases NA release, decreases excitaiton.

Question 19

What is the brand name for detomidine and how does it work?

Answer 19

Domosedan. presynaptic alpha2 agonist

Question 20

What is the brand name for metedomidine and how dies it work?

Answer 20

Domitor. presynaptic alpha2 agoinst

Question 21

what is the brand name for dexmedetomidine and how does it work?

Answer 21

dexdomitor. presynaptic alpha2 agonist

Question 22

what is the brand name for romidine and how does it work?

Answer 22

Sedivet. alpha2 agonist.

Question 23

Which of the alpha2 agonist drugs is most specific for the receptor?

Answer 23

Dexmedetomidine.

Question 24

Where to alpha2 agonists act for sedation and what other effects do they cause?

Answer 24

locus coerulus. Also cause analgesia, hypertension, bradycardia, emesis and hypotension, hyperglycaemia, ADH inhibition (causes urination), decrease plasma cortisol, increase growth hormone release.

Question 25

How are alpha2 agonists metabloised and excreted?

Answer 25

Liver, kidney

Question 26

Give an example of an alpha2 antagonist licenced in the UK

Answer 26

Atipamezole.

Question 27

What is Atipamezole used for?

Answer 27

reverse medetomidine and other alpha2 agonists.

Question 28

What dose of atipamezole should be used?

Answer 28

around 5 times that of the medetomidine dose. Leave 20minutes before reversing agonists,

Question 29

Give three examples of Benzodiazepine drugs

Answer 29

Diazepam, midazolam and zolazepam

Question 30

What is the mechanism of action of benzodiazepines?

Answer 30

Increases GABA affinity so increases inhibitory pathway also slows recovery of voltage gated sodium channels

Question 31

When are Benzodiazepines used?

Answer 31

Sedation in very yung/ old/ sick patients.

Question 32

What other actions do benzodiazepines have?

Answer 32

amnesia, anticolvulsant, muscle relation, appetite stimulant

Question 33

What dose of diazepam should be used?

Answer 33

0.2-0.5mg/kg

Question 34

what does of midazolam should be used?

Answer 34

0.2-0.5mg/kg

Question 35

What should be used to reverse the action of Benzodiazepines?

Answer 35

Flumazenil

Question 36

Give examples of butyrophenones.

Answer 36

Haloperidol, droperidol, fluroperidol, azaperone.

Question 37

What is the manufacturing name of azaperone and what species is it used in?

Answer 37

Stressnil. Pigs, elephants

Question 38

What is the mechanism of action of butyrophenones?

Answer 38

dopamine antagonist. Also act on histamine, cholinergic and 5HT receptors.

Question 39

when is ketamine used?

Answer 39

Used commonly in cats at subanaesthetic doses. combination with medetomidine or benzodiazepine. Often in feral or fractious animals.

Question 40

What does of ketamine should be used for sedation in cats?

Answer 40

2-5mg/kg.

Question 41

When is alfazalone used for sedaiton?

Answer 41

subanaeasthetic doses in high risk/ sick animals. Used in small dogs and in combo with benzodiazepines.

Question 42

what other types of drugs may be used in a pre-med?

Answer 42

opiods (butorphanol, buprenorphine, methadone, morphine, fentanyl), NSAIDS (carprogen, meloxicam in small animals, flunixin in cattle and horses and phenylbutazone in horses). Anticholinergics eg atropine (not really used any more).