Premedication and Sedation

Question 1

What is predmedication?

Answer 1

administration of medication before anaesthesia

Question 2

What is anxiolysis?

Answer 2

state of mental calm and relaxation, decrease in locomotor activity and reduced anxiety, lack of concern for the surrounding environment

Question 3

What is sedation?

Answer 3

state of mental calm and sleepines, disinterest in the environment, poor response to stimuli compared to an anxiolytic

Question 4

What is narcosis?

Answer 4

sedation provided by opiods

Question 5

What is neuroleptoanalgesia?

Answer 5

joint administration of a sedative drug and an opiod analgesic especially for relief of surgical pain

Question 6

Why should we premedicate?

Answer 6

• Decreases anxiety, stress and catecholamine release
• facilitates handling and iv placement
• promotes smooth indcution
• decreases ANS activation during surgery

Question 7

What is the issue with acepromazine?

Answer 7

• Syncope (fainting)
• Anti-Arrhythmia effect
• May effect collies and shepherds with the MDR-1 gene mutation

Question 8

What does the alpha-2 adrenergic receptor effect?

Answer 8

• activation of the central and peripheral pre and post-synaptic alpha 2 receptors
• effects the alpha 1 and imidazolie receptors

Question 9

What may act as an agonist to the alpha 2 adrenergic receptor?

Answer 9

• MEDETOMIDINE & DEXMEDETOMIDINE (dog, cat)
• XYLAZINE (horse, cattle)
• DETOMIDINE (horse, cattle)
• ROMIFIDINE (horse)
• ZENALPHA (dog)

Question 10

What are the general effects of alpha 2 agonists?

Answer 10

• analgesia
• hyperglycaemia
• muscle relaxation
• sedation and anxiolysis
• emesis and decreased gut motility

Question 11

What are the cardiovascular effects of alpha 2 adrenergic?

Answer 11

• Peripheral vasoconstriction
• reflex bradycardia

Question 12

What are the antagonists of alpha-2 adrenergic receptor agonists

Answer 12

• Atipamezole
• Yohimbine
• Tolazoline

Question 13

What receptors do opiods react with?

Answer 13

opiod receptors, mu, kappa and delta

Question 14

Where are opiods excreted?

Answer 14

opiods are excreted in the urine and bile

Question 15

What is methadone?

Answer 15

Full mu agonist
not very sedative
Controlled drug
licensed in dogs and cats

Question 16

What is fentanyl?

Answer 16

• u agonist
• Onset 1-2 mins
• short duration of 20 minutes
• can cause respiratory depression
• licensed in dogs

Question 17

What is buprenorphine?

Answer 17

• Mu partial agonist
• has mild respiratory and cardiovascular effects
• Controlled drug
• licensed in dogs, cats and horses

Question 18

What is pethidine?

Answer 18

• mu agonist
• sedation and analgesia
• some anticholinergic activity
• pain on injection

Question 19

What is butorphanol?

Answer 19

• mu antagonist
• kappa agonist

Question 20

What does butorphanol do in horses?

Answer 20

increases locomotor activity, ataxia and excitement

Question 21

What is trazodone?

Answer 21

• anxiolytic/ sedative
• tricyclic antidepressant
• SSRI’s
• can cause serotonin syndrome

Question 22

Name 5 alpha-2 adrenergic agonists

Answer 22

1. Dexmedetomidine, Medetomidine
2. Xylazine
3. Detedomidine
4. Zenalpha
5. Romifidine

Question 23

How are alpha-2 adrenergic agonists usually administered?

Answer 23

as a bolus, or constant rate infusion

Question 24

What is atipamezole?

Answer 24

Antagonist of the alpha-2 adrenergic receptor agonists
* No IV given unless CPR
* muscle tremors, excitement…

Question 25

What are bothdiazepam and Midazolam?

Answer 25

Licensed benzodiazepines

Question 26

What can both bothdiazepam and Midazolam cause in cats?

Answer 26

Hepatic metabolism and hepatic necrosis

Question 27

What is the known antagonist for Diazepam and Midazolam?

Answer 27

Flumazenil

Question 28

What is the mechanism of action for benzodiazepines?

Answer 28

acts on GABA A receptors

Question 29

Name three opiods

Answer 29

• Fentanyl
• Methadone
• Naloxone

Question 30

What is morphine?

Answer 30

Mu agonist * Histamine release
* Emetic (esp IM/SC) * Epidural (preservative free) * Urinary retention
* Pruritus * Horses
* Controlled drug (schedule II)

Question 31

What is methadone?

Answer 31

Full mu(μ) agonist * NMDA receptor antagonist * Analgesia 
* Not very sedative (apart from sick & very young patients) * Potency: ~ to morphine
* Duration of action 3-4h
* Dose 0.1-0.5mg/Kg IV/IM/SC/transmucosal * Controlled drug (schedule II) * Licensed (dog, cat)

Question 32

What is fentanyl?

Answer 32

µ agonist * Potency: 100 x morphine
* Onset: 1-2 mins
* Short Duration: 20 mins
* Bolus (1-2 mcg/kg) + Constant rate infusion (CRI) (5 -10 mcg/kg/hr) * IV or transdermal patches * Respiratory depression * Controlled Drug (schedule II) * Licensed in dogs

Question 33

What is buprenorphine?

Answer 33

Mu(μ) partial agonist * Weak kappa (κ), & delta (δ) antagonist * High affinity binding to the receptors
* Onset of action: 30 min
* Long duration of action (6-8h) * Analgesic effect (moderate) * Mild respiratory & cardiovascular effects, less nausea/vomiting * Dose 0.01-0.02mg/Kg IM/IV/SC/OTM
* Controlled drug (schedule III) * Licensed in dog, cat, horse

Question 34

What is pethidine?

Answer 34

mu(μ) agonist * ONLY IM administraƟon → Histamine release (IV) * 1/10th morphine’s potency
* Sedation & analgesia
* Some anticholinergic activity
* Dose 3.5- 10mg/kg IM
* Duration of action: 1-2h
* Pain on injection
* Controlled drug (Schedule II) * Licensed in dog, cat & horse

Question 35

What is gabapentin?

Answer 35

Neuropathic pain/ seizures
* Blockage of Ca2+ channels presynaptic neurons →↓ Ca2+ influx→ ↓ excitatory
neurotransmitters
* Side effects: Sedation, ataxia, vomiting, diarrhoea, increased appetite?
* 100 mg/cat 1-2h before veterinary visit