Its all about those drugs

Start with this

Pls don't bully me if I misspell some things, goodluck

What are commonly used inhalation anesthetics?

1. Isoflurane

2. Sevoflurane

3. Desflurane

Less commonly used inhalant anesthetics:

1. Methoxyflurane

2. Nitrous oxide

3. Halothane

New: xenon

Considerations of selecting an inhalation agent:

❀ metabolic

❀ Anesthetic potency

❀ Rate of induction, recovery, and rate of recovery

❀ Cardioplumonary consideration

❀ moniiiiii $$$

Major elimination route of inhalation anesthetics are done through the _________

respiratory tract

Isoflurane %

❀ 0.17%

(metabolized by the liver and kidneys)

Sevoflurane %

❀ 3.0%

(metabolized in the liver and kidneys

Why do we not use nitrous oxide?

❀ not spare other inhalant much

❀ requires higher fresh gas (02) flow

❀ Diffusion hypoxia

What does MAC stand fo foolll?

Minimum alveolar concentration

What does MAC mean?

The concentration of a vapor in the alveoli of the lungs that is needed to prevent movement (motor response) in 50% of subjects in response to surgical (pain) stimulus

Clinically surgical plane of anesthesia is __________ times of MAC

1.5-2

Anesthetic Potency %'s

Isoflurane:

Dog- 1.28%

Cats- 1.68%

Sevoflurane

Dog- 2.36%

Cats- 2.58

The ________ the MAC, the _________ potent the anesthetic agent

less, MORE

True or false: Isoflurane is less potent than sevoflurane

false, Sevoflurane is less potent requiring higher % meaning more $$$

As anesthetic dose increases, mean arterial pressure is _______

decreased= most potent vasodilator

Decreasing MAC factors

❀ Hypotension (ex) hemorrhage intra-op

❀ Hypothermia

❀ Metabolic acidosis

❀ Extreme hypoxia (PaO2 <38 mmHg)

❀ Age

❀ Premedication (opioids, sedatives, tranquilizers)

❀ Pregnancy

Increasing MAC factors:

All your hypers!

❀Hyperthermia

❀Hyperthyroidsm

(increased release of thyroid hormones)

❀Hypernatremia

(sodium concentration is too high)

❀ Drugs increase CNS catecholamines (the good stuff aka cocaine, tricyclic antidepressants)

NOT increasing MAC factors

❀ type of stimulation

❀ duration of anesthesia

❀ species

❀ sex

❀ PaCO2 or PaO2

The higher the blood/gas solubility, the _____ the induction and recovery rates

slower

Rate of induction, Rate of change in anesthetic depth and Rate of recovery CHART

During anethesia, which inhalant can be changed faster when it comes to depth of anesthesia

sevoflurane

Whats one disadvantage of using inhalant anesthetics?

Patients hold breaths due to the pungent smell

Debilitating patients require reduced or increased inhalant anesthetic %?

reduced

Nasotracheal intubation is suitable for?

foals and calves calves are more difficult to be nasotracheal intubated

Lets talk money, whats the ranking of which ones more expensive

Most expensive: desflurane

to...

sevoflurane -> isoflurane -> halothane (least expensive)

Anesthesia maintenance

❀Methoxyflurane: 0.5 - 1.5%

❀ Isoflurane: 1 - 2.5%

❀ Sevoflurane: 2.5 - 4.0%

What can recovering from an inhalant cause?

Dysphoria

(how i feel everyday)

Once you turned off the inhalant vaporizer, keep the patient....

on oxygen for at least 5 mins

General anesthesia process:

1. pre-medications

2. Induction (injectable anesthetics)

3. Maintenance (inhalant/ injectable anesthetics)

Why do we give premeds?

to decrease stress/anxiety

What should you remember when patient is under sedation?

☆ NEVER EEEVAAAAAAA trust a sedated animal

☆ Support spine/muscle

(use transport table)

Why use chemical restraint?

To provide proper restraint and to decrease the chance from getting injury for both your patient and yourself

Pre-emptive analgesia

☆ before pain occurs, control and treat pain

☆ recovery from surgery is faster

☆ control pain, decrease other drug dosage

What are the pre-medication drugs?

1. Phenothiazine (major tranquilizers)

2. Benzodiazepines (minor tranquilizers)

3. Alpha 2 agonists

4. Opioids

5. Anticholinergics

Phenothiazines

Acepromazine

Butyrophenones

☆ droperidol (innovar-vet)

☆ azaperone (Stresnil)

Mechanism of action of major tranquilizers

☆ dopamine antagonists

☆ high doses have negative effects: tremor, rigidity, catalepsy

Acepromazine: concentration

Phenothiazine

(10 mg/ml)

Note: bottle dose is 10 times the recommended dose!

Acepromazine: dosage

Dog: 0.01-0.05 mg/kg

Cat: 0.02-0.1 mg/kg

Horse: 0.005-0.02 mg/kg

3 multiple choice options

Acepromazine: injection sites

Dog and Cat: IM, SQ, IV

Horse: IV, IM

Acepromazine: clinical uses

☆ decrease anxiety

☆ NO ANALGESIA

☆ Dose dependent: use at low doses

☆ chaaa epppp

Acepromazine- 3 "anti-"

☆ antiarrythmogenic

☆ antiemetic

☆ antihistamine

Acepromazine: cardiovascular effects

☆ HYPOTENSION

(due to alpha 1- adrenergic blockade)

Acepromazine: other effects

☆ minimal respiratory effects

☆ mild H-1 antihistaminic properties

☆ extrapyramidal signs at a high dose (rigidity, tremors, catalepsy)

Controversial: lower seizure threshold

Why don't we use phenothiazine in breading stallion?

Can cause penile prolapse (ouch!)

Acepromazine: duration

NOT REVERSIBLE

☆ last for several hours (long acting)

Acepromazine: method of elimination

☆ hepatic metabolism

(effects may be prolonged with hepatic disease/ neonate/ geriatric patients

Butyrophenones:

☆ droperidol (similar to phenothiazine)

☆ azaperone (use in swine primary) This can be used with other drugs like butorphanol, azaperone, and medetomidine

Benzodiazepines:

- diazepam

- midazolam

- zolazepam

- flumazenil

Which one is an antagonist?

flumazenil

3 multiple choice options

Benzodiazepines: mechanism of action

agonists at benzodiazepine receptor sites in the CNS; these receptors potentiate the effects of GABA (an inhibitory neurotransmitter) in the CNS

Benzodiazepines: Clinical uses:

☆ mild sedation effects (not dependable)

☆ central muscle relaxant properties

☆ useful sedatives in debilitated animals or neonates

☆ good sedative in camelids, small rumiants

☆potent anticonvulsants (prevents seizures)

Benzodiazepines: Cardiopulmonary effects

NONE!

☆ maybe some mild hypotension and respiratory depression

☆ if given a bolus, may see apnea

Benzodiazepines: adverse effects

☆ may see excitement/agression when given alone

☆usually only used if patient is pediatric/ geriatric or debilitated

do NAWT give ________ Benzodiazepines!!!!

cats

Which is water soluble

midazolam

2 multiple choice options

Which IS irritating to the tissue:

diazepam

2 multiple choice options

Diazepam site

IV or rectally

Midazolam site

IM or SQ

Benzodiazepines: duration

In general: relatively short!

Up to an hour: diazepam/midazolam

D: antiseizure effects may be shorter, duration effects may be greatly prolonged in geriatrics

M: little change with geriatric

Species dependent:

zolazepam

Benzodiazepines: dosage

Diazepam and: 0.2-0.4 mg/kg

What is benzodiazepine reversible with?

flumazenil

Alpha-2 Adrenergic Agonists

Main ones:

-dexmedetomidine (Dexdomitor)

-xylazine (Rompun)

-detomidine (Dormosedan)

Alpha-2 Adrenergic Agonists: reversals

-yohimbine (yo... he fine) (yobine)

-tolazoline (priscoline)

-atipamezole (antisedan)

Alpha-2 Adrenergic Agonists: mechanism of action

☆ agonist activity at alpha-2 adrenergic receptors

☆ results in decrease in release of norepinephrine from adrenergic nerve terminals in CNS and periphery

☆ cases sedation, decreased sympathetic activity, analgesia

Why use alpfhufuej (cat stepped on keyboard) alpha- 2 adrenergic

☆ great sedation

☆ excellent analgesia

☆ muscle relaxation

REVERSIBLE

Alpha-2 Adrenergic Agonists: cardiopulmonary effects

☆ SEVERE bradyarrythmias (slow heart rate)

-do NAWT treat w atropine-

☆ negative inotropic effect: decrease cardio output

☆ Biphasic effect on blood pressure

☆ mild respiratory depression alone

☆ stridor & dyspnea in horses + brachycephalic dawgz

Alpha-2 Adrenergic Agonists: other effects

☆RUMINANTS ARE EXTREMELY SENSITIVE

-least sensitive is swine)

☆ decrease GI activity

☆ cause vomiting in cats and dogs

☆abortion in cattle

☆increased urination

☆sweating

☆hyperglycemia

☆horses may kick

Alpha-2 Adrenergic Agonists: duration of action

ALL DOSE DEPENDENT

Xylazine: up 30 mins

Detomidine: up to 2 hrs

Dexmedetomidine: up to 1 hr

Alpha-2 Adrenergic Agonists: xylazine

Dogs/cats: 0.1-0.5mg/kg IM, SQ, IV

Horse: 1.0 mg/kg, IV or IM

Ruminants: 0.44- 0.1 mg/kg IV or IM

Alpha-2 Adrenergic Agonists: detomidine

ONLY FOR HORSES

0.01-0.02 mg/kg IV

Alpha-2 Adrenergic Agonists: dexmedetomidine

3-30 mcg/kg IV, IM

Alpha-2 Adrenergic Agonists: reversals dosage

☆yohimbine: (0.1 - 0.15 mg/kg, IM)•

☆tolazoline: (1 - 1.5 mg/kg, IM) - do not use in llama andalpaca

☆atipamezole: (0.1 mg/kg, IM or IV) - usually give same volume of dexmedetomidine

What is Zenalpha?

☆ Medetomidine + Vatinoxan

☆ vatinoxam works in the periphery

☆ medetomidine: sedation and analgesia

☆Improved cardiac output

☆ONLY FOR DAWGGGSS IM

☆less bradycardia and not induced vasocontriction compared to dexmedetomidine

Name me some opioids or else

☆ morphine

☆ hydromorphone

☆ fentanyl

☆ methadone

☆ meperidine

☆ buprenorphine

☆ butrophanol

☆ nalbuphine

☆ naloxone

Full agonist opioids

☆ morphine

☆ hydromorphone

☆ fentanyl

☆ methadone

☆ oxymorphone

☆ meperidine

(produces good sedation and analgesia- treats moderate to severe pain)

Partial mu agonist

buprenorphine

(produces good analgesia but NOT good sedation- treats mild to moderate pain)

Agonist (kappa) & Antagonist (mu)

☆ butorphanol

☆ nalbuphine

(NOT good analgesia but good sedation- treats mild pain)

Its used for partial reversal of full agonist opioid

Full antagonists

☆ naloxone

☆ naltrexone

(reverses sedation and analgesia completely)

Opioids: Clinical uses

☆ sedation

☆ analgesia

Opioids: cardiopulmonary effects

☆ bradyarrhythmia (easy to correct with anticholinergics)

☆ respiratory depression (decrease tidal volume and increase panting)

☆minimal effect on blood pressure

☆Histamine release for morphine, meperidine --> vasodilation hypotension

Opioids: other effects

☆ 3P: poop, pee, puke

☆ #addictive

Hydromorphone dosage

2mg/ml

Dose: 0.05 ~ 0.2 mg/kg, IM, SQ or IV

(usually 0.1 mg/kg as premed)

Hydromorphone duration

Long acting: 2-4 hours (dose dependent)

Hydromorphone why do we use

☆ produces good sedation and analgesia

☆ treats moderate to severe pain

☆ less likely to cause histamine release

☆Bradyarrhythmia

Morphine: dosage

15 mg/ml or 1 mg/ml

☆ 0.5-1 mg/kg IM or SQ

☆ 0.1 mg/kg (epidural)

Morphine: duration

2-4 hours

Morphine: why do we use

☆ treats moderate to severe pain

☆ sedation and analgesia

☆ cheap

☆ Histamine release- give IV injection (CRI)!!!!

Cat: morphine mania

Fentanyl dosage

50 mcg/ml

wtf idek what to say

☆2-5 mcg/kg IV bolus

☆5-50 mcg/kg/hr IV CRI

☆ 2-5 mcg/kg/hr IV CRI

Fentanyl duration

Short: 10-15 mins use CRI

Fentanyl why do we use

☆ produces good sedation/ analgesia

☆ treat moderate to severe pain

Fentanyl dermal patch

☆good for home pain control

☆not great choice for anesthesia protocol

☆Long duration: 72 hours

Over dosage... sedation & bradyarrythmias

Methadone dosage

10 mg/ml dawgs and kats

☆ full agonist opioid

0.1-0.2 mg/kg SQ,IM, IV

Methadone duration

2~4 hours (redoes 2 hrs)

Methadone why we use

☆ good sedation/ analgesia

☆ treat moderate to severe pain

Buprenorphine dosage

0.3 mg/ml kats

0.005- 0.04 mg/kg

IV,IM, SQ, transmucosally

Buprenorphine duration

6-8 hours, onset can be slow (~30 mins)

Buprenorphine why we use

☆ mild sedation/ moderate analgesia

SIMBAadol

1.8 mg/ml

lol get it. SIMBA cus like cats... yeah ok

Duration: 24 hrs

Dosage: 0.24 mg/kg SQ

Causes: hypotention, hyper/hypothermia, tachycardia

Zoribum

☆only for cats

☆ up to 4 days

☆ apply 1-2 hours before surgery