Lecture 11: Premedications Flashcards by Jen McGann

What is neuroleptoanalgesia

Combined sedative and opioid

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What is ASA status 1

Healthy patient

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What is ASA status 2 and some examples

Mild systemic disease
Ex: skin tumor, fracture without shock, uncomplicated hernia, cryptorchid, localized infection, compensated cardiac disease

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What is ASA stratus 3 and some examples

Severe systemic disease
Ex: Hypovolemia, fever, dehydration, anemia, cachexia

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What is ASA status 4 and some examples

Severe systemic disease that threatens daily life
Ex: severe hypovolemia and dehydration, cardiac disease, very high fever, uremia, toxemia, anemia, emaciation

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What is ASA status 5 and some examples

Patient won’t severe more than 1 day without tx
Ex: extreme dehydration, shock, terminal malignancy or infection, severe trauma

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What is the mechanism of action for acepromazine

Dopamine and alpha1 receptor antagonist

Also Muscarinic, histamine and serotonin antagonist

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What are the effects of acepromazine on CNS

Sedation, muscle rigidity with high doses

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What are the cardiovascular effects of acepromazine

Vasodilation/hypotension- decrease CO
Anti-arrhythmic- alpha 1

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What are the respiratory effects of acepromazine

Minimal- decrease RR and increase TV, bronchodilator

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What are the hematologic effects of acepromazine

Decrease PCV, inhibit platelet aggregation, anti-histamine

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What are the GI effects of acepromazine

Anti-emetic, decrease LES tone, decrease gastric emptying

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What can acepromazine cause in horses

Penile prolapse

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What does acepromazine do to urethral sphincter

Relaxes

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Does acepromazine provide analgesia and is there a reversal

No to both

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What are some side effects of acepromazine

Vasodilation-hypotension, decreased platelet aggregation, muscle rigidity, splenic enlargement, hypothermia

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What is the onset of action of acepromazine IV and IM

IM- 30 minutes
IV-5-10 minutes

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What is the duration of effect of acepromazine

4-6hrs

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When should you reduce dose of acepromazine

IV dose, geriatrics, and large breeds

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When do you use acepromazine

Healthy patients undergoing simple surgeries- spay, neuter, orthopedic

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When do you be cautious using acepromazine

Bleeding or anemia, stallions, neonates, thrombocytopenia

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What species is the most sensitive/requires lowest dose for alpha2 agonists

Cattle

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What are the effects of alpha2 agonists on CNS

Sedation, anxiolytic, bradycardia

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What are the cardiovascular effects of alpha2 agonists

1st phase- vasoconstriction and bradycardia
2nd phase- vasodilation and bradycardia
Bradyarrythmias- AV block, sinus bradycardia, ventricular arrhythmias
Decrease CO

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What are the effects of alpha2 agonist on respiratory system

Respiratory depression, increase TV

What are the effects of alpha2 agonists on GI

Emesis (xylazine-cats) Decrease GI motility

What are the effects of alpha2 agonists on urogenital

Increase urine production and increase uterine pressure

Do alpha2 agonists cause hyperglycemia or hypoglycemia

Hyperglycemia

What is the effect of alpha2 on muscles

Muscle relaxers

Do alpha2 agonist provide analgesia and is there a reversal

Yes to both

What are some side effects of alpha 2 agonist

Ileus, respiratory depression, bradycardia and hypertension, followed by hypotension, hyperglycemia, ataxia

What is the onset of action for alpha2 agonists IV, IM, transmucosal

IV: 1-5 mins IM: 5-20 Transmucosal: 30-40mins

What is the duration of action of alpha2 agonists

30-60 minutes

When do you want to treat bradycardia associated with alpha2 agonists

Don’t treat in first phase when hypertensive and bradycardia because will increase HR and BP, wait for second phase when hypotension and bradycardia

When should you avoid use of alpha2 agonists

Sheep-pulmonary edema- death Pregnancy- esp. 1st trimester

Zenalpha- medetomidine and vatinoxan: what is it used for and why is it better than just medetomidine alone

Approved for dogs for sedation (not undergoing GA) Vatinoxan is an alpha2 peripheral antagonist so don’t have the CV effects- no hypotension/vasoconstriction and reflex bradycardia

What is the onset time for zenalpha and duration of action

Onset: 5-15 minutes Duration: 30-45 minutes

What is the most and least selective alpha2 agonist

Most: dexmedetomidine Least: xylazine

What are the alpha2 antagonists/ reversals

Aitpamezole, yohimbine, tolazoline

What are the effects of alpha2 antagonists

Reversal of analgesia and sedation

What is the mechanism of action of benzodiazepines

GABA agonists

What are the effects of benzos on CNS

Sedation, anxiolytic, amnesia, anticonvulsant, MAC sparing effects

What are the effects of benzos on cardiovascular and respiratory systems

Minimal

T or F: benzos relax muscles

True

Do benzos provide analgesia and is there a reversal agent

No analgesia, yes reversal (flumazenil)

What is the onset for IV and IM for benzos

IV: 2-5 minutes IM: 15-20 minutes

What is the duration of action for benzos

30-45 minutes

How does midazolam and diazepam differ in their routes of administration

Midaz: IV, IM, or PO Diazepam: IV or PO - can’t give diazepam IM because painful and effects are inconsistent

Benzodiazepines are good sedation options for what types of patients

Neonates, geriatrics, exotics, pigs, small ruminants

Benzos can cause paradoxical ___ and disinhibition causing ___

Excitation, aggression

Benzos are a good muscle relaxant and therefore good co-induction/sedative with ___ and ___

Ketamine, etomidate

Benzos can be used as an ____ in cats and goats

Appetite stimulant

In what scenarios should you use caution with benzos

Pregnancy- crosses BBB and placentas Hepatic disease

What is the reversal agent for benzos

Flumazenil

What opioids are full u receptor agonists

Morphine, methadone, fentanyl, hydromorphone

What opioids are partial u receptor agonists

Buprenorphine

What opioids are both an agonist/antagonist

Butorphanol

What are the reversals for opioids

Naloxone and naltrexone

What is the mechanism of action of opiods

U or k receptor agonists

What are the effects of opioids on the CNS

Sedation, analgesia, MAC sparing, dysphoria, euphoria

What are the cardiovascular effects of opioids

Bradycardia Morphine- histamine release- vasodilation/ hypotension

What opioid is known to cause release of histamine and vasodilation

Morphine

What are the respiratory effects of opioids

Respiratory depression, tachypnea (panting)-thermoregulation

What are the GI effects of opioids

Nausea, vomiting, decreased GI motility

What opioids do not cause vomiting and nausea

Methadone, fentanyl, butorphanol

What are the effects of opioids on urogenital system

Urinary retention

Do opioids cause hypo or hyperthermia in cats and which ones

Hyperthermia with hydromorphone, morphine, and buprenorphine

What are the effects of opioids on the pupils

Dogs, rabbits: miosis Cats and horses: mydriasis

Do opioids provide analgesia and is there a reversal

Yes to both

What are some side effects of opioids

Decrease GI, vasodilation, respiratory depression, tachypnea, euphoria, dysphoria, regurgitation, vomiting, excitement in horses, bradycardia, hyperthermia in cats, histamine release

What is the onset of action for opioids IM and IV

IM: 5-20 minutes IV: 1-5 minutes

What is the duration of action for morphine, methadone, and hydromorphone

4-6hrs

What is the duration of action for fentanyl

15-30 minutes

What is the duration of action for buprenorphine

6-8hrs

what is the duration of action for butorphanol

1hr

Methadone is a ____antagonist so also good at treating chronic pain

NMDA antagonist

Is buprenorphine better at treating pain or causing sedation

Mild to moderate tx of pain, not good pre-med because long onset and minimal sedation

Is butorphanol better at treating pain or sedation

Mild analgesic and good sedation

When should you avoid use of opioids

Pregnancy, use of more than 1 opioid

What species is simbadol approved for and what is duration of effect

Cats, 72hrs

What species and route is Zorbium approved for and how long is duration of effect

Cats, transdermal, 96hrs

What is the mechanism of action for alfaxalone

GABA agonist

What is alfaxalone used for

Sedation/immbolization

What is a possible side effect of alfaxalone

Tremors, rough recovery, vasodilation, hypotension, apnea

T or F: alfaxalone is analgesic

False

What type of anesthesia does ketamine/ tiletamine cause

Dissociative anesthesia

T or F: ketamine/ tiletamine is analgesic

True

Which crosses BBB and placenta: atropine or glycopyrolate

Atropine

What is the drug of choice for CPR

Atropine

Which produces less profound tachycardia: atropine or glycopyrolate

Glyco

When do you want to use anticholinergics (atropine, glyco)

Bradycardia associated with hypotension, ocular surgery, brachycephalic, pediatrics

What are some side effects of anticholinergics

Tachycardia, tachyarrhythmias, decrease GI (avoid in horses), reduce secretions but make them thicker, increase of LES

When should you use caution with anticholinergics

Heart disease, hypothermic patients

What antihistamine is commonly used in a premed when there is risk of allergic reactions, MCT, reaction to surgical prep

Diphenhydramine

When would you want to use GI protectant like famotidine, pantoprazole in premed

Brachycephalics and GI sx

When do you want to use antiemetics (maripotant, metoclopramide, ondansetron) in premed

Brachycephalics and GI sx

What drugs can be used for chill protocol and what species

Gabapentin- dogs and cats Trazodone-dogs Acepromazine- dogs Melatonin-dogs