Anesthetic Agents through Alpha 2 Agonists

An anesthetic agent is described as…

any drug used to induce a loss of sensation (with or without loss of consciousness)

An adjunct is described as…

an agent that is used during anesthesia to produce supporting effects but is not a true anesthetic

Adjuncts may be used to produce…

sedation

muscle relaxation

analgesia

reversal

neuromuscular blockade

parasympathetic blockade

Sometimes general anesthesia produces unconsciousness but not…

pain control

If a patient is still experiencing pain under general anesthesia, it will be difficult to control when…

a patient regains consciousness

Some drugs are incompatible, when they are mixed the following can occur…

loss of potency

change in chemistry

precipitation

Primarily, diazepam can be mixed with _______ but not most other drugs.

ketamine

The classes of drugs used as pre-meds include…

anticholinergics

tranquilizers and sedatives

opioids

Examples of tranquilizers and sedatives include…

phenothiazines

benzodiazepines

alpha 2 agonists

A stormy induction/recovery is described as…

agitation, thrashing, vocalization, generally high stress

In addition to being used as a pre-med, tranquilizers can be used to…

transport

wound care

radiographs

In addition to being used as a pre-med, benzodiazepines can be used as…

anticonvulsants

In addition to being used as a pre-med, opioids can be used for…

cough suppression

Anticholinergics are used to…

prevent and treat bradycardia
decrease salivary secretions

The two most common anticholinergics are…

atropine

glycopyrrolate

The primary neurotransmitter of the parasympathetic nervous system is…

acetylcholine

The two receptors the acetylcholine can bind to are…

nicotinic

muscarinic

Anticholinergics work by…

blocking the binding sites of acetylcholine at muscarinic receptors

The main nerve of the parasympathetic nervous system is the…

vagus nerve

Anticholinergics are used to reverse and prevent the following…

bradycardia

bronchoconstriction

excessive tear and saliva

excessive respiratory secretions

increased GI motility

The peak effect for atropine will occur ___ minutes after IM administration.

15-20 minutes

The duration of atropine is about…

60-90 minutes

The peak effect for glycopyrrolate will occur ___ minutes after IM administration.

35-40 minutes

The duration of glyccopyrrolate is about…

2-3 hours

The peak effect for atropine will occur ___ minutes after IV administration.

3-4 minutes

Anticholinergics are not sedatives, so they have minimal…

effects on the CNS

True or false: Glycopyrrolate does not cross the blood brain barrier

true

At low doses, atropine can cause…

bradycardia

After atropine is administer IV, it may have the following effect on the cardiovascular system…

temporary first or second degree atrioventricular block, followed by sinus tachycardia

True or false: Atropine is more likely to cause arrhythmia than glycopyrrolate.

true

Anticholinergics are contraindicated for patients…

with pre-existing heart disease

Anticholinergics are contraindicated for cats and ruminants because…

they overly thicken respiratory and salivary secretions, risking blockages

Bronchodilation is described as…

an increase in the diameter of bronchioles

Bronchodilation can cause risk for…

hypoventilation

hypoxemia

Mydriasis is described as…

dilation of the pupils

Miosis is described as…

constriction of the pupils

Which anticholinergic is less likely to produce cardiac arrhythmia?

glycopyrrolate

Which anticholinergic better suppresses salivation?

glycopyrrolate

Which anticholinergic crosses the placental barrier less?

glycopyrrolate

Which anticholinergic is more affordable?

atropine

Which anticholinergic is better for emergencies?

atropine

Atropine is a better anticholinergic for emergencies because of…

it’s rapid onset of action

Tranquilizers are defined as medications that…

reduce anxiety without effect on awareness

Sedatives are defined as medications that…

reduce brain activity and awareness

General adverse effects of tranquilizers and sedatives may include…

ataxia

prolapse of the nictitating membrane

Brachycephalic breeds can experience respiratory distress when administered tranquilizers/sedatives because…

they relax the tissue of the pharynx

The main phenothiazine used in anesthesia protocols is…

acepromazine

Acepromazine is approved to be used in the following species…

dogs, cats, horses

Acepromazine is approved to be administered through the following routes…

IV or IM

Acepromazine blocks the following receptors…

alpha-adrenergic

dopamine

histamine

Acepromazine is metabolized by the…

liver

Acepromazine causes depression of the…

reticular activating center in the brain

The peak effect for acepromazine will occur ___ minutes after administration.

30-60 minutes

In small animals, the duration of acepromazine is about…

4-8 hours

In horses, the duration of acepromazine is about…

1-3 hours

Acepromazine creates the following effects on the CNS…

calming

reluctance to move

decrease interest in surroundings

True or false: Acepromazine provides pain control.

false

As an anti-arrhythmic, acepromazine can protect against…

ventricular arrythmias

Acepromazine can cause __________ due to hypotension.

tachycardia

Acepromazine can cause __________ at high doses.

bradycardia

Acepromazine is contraindicated for patients with…

hypotension associated with shock, blood loss, or dehydration

Alone acepromazine does not cause significant respiratory changes, but when mixed with other anesthetic drugs it can…

create increased depressive effects

Acepromazine can have an antiemetic effect because it blocks…

dopamine receptors

Acepromazine is contraindicated in breeding stallions because it may cause…

penile prolapse

Acepromazine may decrease PCV is dogs and horses because…

reuptake of RBCs by the spleen increases

Acepromazine can have an antihistamine effect because it…

prevents the release of histamine

If an acepromazine dose is “maxed out” this means…

after a certain dose, sedation will not increase by hypotension will increase

Acepromazine has an increased potency in the following patients…

geriatric

neonates

liver/cardiac dysfunction

debilitated

In horses, if acepromazine is injected intraarterially, this can cause…

severe CNS excitement

seizures

death

To ensure you’re in a vein not an artery you should…

remove the syringe from the needle after venipuncture, if blood flow ceases you’re in a vein - if blood flow continues you’re in an artery

Benzodiazepines are schedule ___ controlled substances.

schedule 4

The most common benzodiazepines used for anesthesia include…

diazepam, midazolam, zolazepam (as part of telazol)

Benzodiazepines can cross the placental barrier, causing…

CNS of neonates during c-section

Benzodiazepines are mixed with ketamine in order to…

prevent muscle rigidity

In addition to anesthesia protocols, diazepam can be used for…

seizure control

behavior modification

Diazepam is typically combined with _______ for anesthetic induction.

ketamine

If diazepam is given too rapidly IV, it can cause…

pain

bradycardia

hypotension

apnea

Diazepam is stored in brown bottles because…

it’s very light sensitive

The main benzodiazepine used as a preanesthetic tranquilizer is…

midazolam

Midazolam is more compatible to be mixed with other drugs because it is…

water soluble

Midazolam is most reliably absorbed through…

IM injections

Zolazepam is commonly incorporated with…

tiletamine

The reversal agent of benzodiazepines is…

flumazenil

Alpha 2 agonists are described as…

sedative analgesics

In addition to being used in anesthesia protocols, alpha 2 agonists can also be used for…

radiographs

wound treatments

Alpha 2 agonists are reversed with…

alpha 2 antagonists

The most common alpha 2 agonists used during anesthesia are…

xylazine, dexmedetomidine, detomidine, romifidine

Alpha 2 agonists are typically administered…

IV or IM

Alpha 2 agonists decrease the release of…

norepinephrine

Sedation will occur within ____ minutes after administering an alpha 2 agonist IV.

5-15 minutes

Sedation will occur within ____ minutes after administering an alpha 2 agonist IM.

15-30 minutes

The duration of alpha 2 agonists is about…

1-2 hours

Without reversal, it may take ____ hours to recover from alpha 2 agonist effects.

2-4 hours

Alpha 2 agonists are best for ____ pain.

visceral

When alpha 2 agonists are on board, which will wear off first — sedative or analgesic effects?

analgesic

Why would fear and stress before administration of alpha 2 agonists hinder the ability to produce sedation?

alpha 2 agonists only stop the production of new norepinerphine, it does not have any effect on existing norepinerphine present

Alpha 2 agonists can also stimulate alpha 1 receptors, causing…

vasoconstriction

Vasoconstriction may lead to…

hypertension

bradycardia

Alpha 2 agonists create a dramatic decrease in heart rate when used alone, dogs can have a heart rate as low as…

30-50 bpm

Alpha 2 agonists are contraindicated for…

geriatric

cardiovascular disease

respiratory disease