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207 Cards in this Set

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What are the 4 phases of anesthesia?


Maintenance & Monitoring

What anesthesia concerns are there with brachcephalic breeds?
*airway obstruction concerns during RECOVERY
*tend to have stenotic nares
*Tracheal diameter tends to be smaller, so a smaller ET tube may be needed
*Increased Parasympathetic/Vagal tone may lead them to become bradiacardic during Sx
*Automatically a 2 on Physical Status/Risk scale due all the above.
Sighthounds tend to have issues with what type of drugs due their low body fat?
When calculating anesthetic meds for an animal, if the animal is overweight, what weight should be used, actual or ideal weight?
Ideal weight should be used

*Brain is same size no matter how fat the animal is**
What is another concern we have with obese patients during anesthesia?
*With have trouble ventilating themselves--Need more ventilatory support

*Are dyspnic, even at rest
What are some concerns we have with emaciated/anorectic patients for anesthesia?
*With these Pt's, we calculate drugs at ACTUAL weight rather than ideal.

*Hypothermia is an issue

*Hypoglycemia can be an issue ---add Dextrose to fluids
What defines the geriatric life phase?
Animal has lived 75-85% of expected lifespan
What is one reason it is important to have fluids going during a Sx for a geriatric patient?
MANY have early sub-clinical kidney failure and maintaining renal perfusion leads to less damage to already damaged kidneys.
Anesthesia leads to a decreased blood pressure, therefore lowering renal perfusion, which kills off nephrons. How do we counteract the effects of lowered BP of anesthesia, thereby SAVING the nephrons?
Give IV fluids to keep BP and therefore renal perfusion up.
What are 2 concerns with geriatric patients and anesthesia?
What is the basic guideline for defining an animal as a neonate?
Less than or equal to 8 WEEKS of age

*Study was done that came to the conclusion that physiologically neonates are the same as adults in regards to how they can process anesthesia. Have the same Kidney and liver function.
What is a concern for neonates during anesthesia?
Hypothermia and hypoglycemia
What is one way to counteract the effects of hypoglycemia in patients where this is a concern during anesthesia?
-With hold food for shorter amount of time
*add dextrose to IV fluids
What are 2 basic rules of thumb for anesthesia with Geriatric and Neonates?
*Use a shorter acting anesthesia since liver is not working as well

*Use a reversible drug that does not need to be metabolized.
In regards to Sex-repro status, what are some items that need to be checked before anesthesia?
*Cyptorchid is an increased surgical risk due to abdominal incision.
*Preg check-pregnant is increased risk
**ALWAYS have fluids going!!.
-If female is closer to term, when uterus and fetuses are being removed, BP will drop drastically, so consider increasing fluids or give a bolus.
*Estrus-increases blood flow to uterus, increase risk for hemorrhage during recovery.
Why are animals with temperament issues a possible increased anesthetic risk?
*Cannot do a P/E, pre-anes bloodwork, so animal is not fully pre-assessed
*Stress can predispose animal to cardiac arrythmias--->respiratory arrest
Duration of problem affects anesthetic risk because_________________
a longer existing problem will have more issues than one that recently started and was quickly caught, diagnosed and corrected.
Concurrent disease should be _____________ prior to anesthesia/Sx.
fixed if possible
If an Pt has a history of seizures, what dugs should be avoided because of their tendency to lower seizure threshhold?
(Diazapam is a good alternative to Ace)
What are some concerns if an animal has Addison's/Hypoadrenocorticism?
-Will have low Na, High K

-These predispose an animal to bradycardia, arrythmia and cardiac arrest

_Should try to fix prior to anesthesia/Sx
What are some concerns if an anima has DKA prior to Sx?
Diabetic Ketoacidosis cause severe metabolic acidosis causing increase in blood ph
Why is there a concern if an animal has liver or kidney disease?
Interferes with drug metabolism
WHat should be done if an animal has heart issues in regards to Sx?
Avoid cardiovascular
Why do we palpate for a pulse?
To determine blood pressure and character of pulse (weak, bounding, thready)
A weak or absent pulse may indicate?
Hypotension due to pulses disappearing when systolic <60mmHg
A bounding pulse indicates?
A pulse deficit indicates?
PVC's due to HR exceeding pulse
Increased CRT and pale MM indicate?
1. Peripheral Vasoconstriction due to cold, pain, alpha-2 agonists

2. Decreased tissue perfusion possibly due to:
Excessive anesthetic depth
Blood loss, anemia
Heart failure
Cynosis is due to ?
Hypoxia, increased amounts of reduced Hg
Liver function is important in regards to anesthesia because?

Metabolism and elimination of anesthesia

Sx-produce clotting factors, albumin for maintaining oncotic pressure
Why is renal function important in regards to anesthesia?
-Anesthetic elimination, regulate distribution of H2O, electrolytes, blood pressure maintanence with Renin production
What are some GI concerns in regards to anesthesia?
Primarily V/D that will cause fluid and electrolyte imbalances, acid base imbalances
-Parasites can cause anemia, diarrhea
-GDV can impair ventilation and depress cardiac output
What is the bare minimum Lab work that should be done prior to anesthesia?
-To diagnose anemia and evaluate O2 carrying capacity
--PCV less that 20-2% CAUSES HYPOXIA-->leads to poor tissue oxygenation
What does TP eval tell us that we need to know prior to Sx?
increased= dehydration
over-hydration, liver disease, protein losing nephropathy, protein losing enteropathy (diarrhea), malnutrition/starvation
What does the CBC tell us in regards to the RBC/Hct/Hgb?
Oxygen carrying capacity
What does the CBC tell us in regards to the WBC?
stress, fear
What does the CBC tell us when we see increased Eos?
Parasite present
What does the CBC tell us in regards to platelet evaluation?
Ability to clot and coagulate
What do blood chemistry/PA panels tell us in regards to Glucose?
pancreatic function test
What do blood chemistry/PA panels tell us in regards to BUN, Creatinine?
Tells us about the GLomerular function of the kidney
-Will be increased (Azotemia) with impaired renal function
-Can be increased with dehydration, shock, hypotension
-BUN may decrease with liver disease
What do blood chemistry/PA panels tell us in regards to ALT/ALK Phos?
Tells us about liver function

ALT increase-hepatocyte damage or destruction

ALK Phos increase indicates HBO, Bone growth/injury
What are the 6 tests the make up the PA panel?
BUN/ Creatinine
ALT/Alk Phos
What does a U/A tell us in regards to pre-anesthesia evaluation?
-Renal tubules are functioning,
-Kidneys are functioning-->concentrating urine
-Hydration status
DIPSTICKS=ph, blood, bilirubin (liver), glucose/ketone , proteins
What is a concern in regards to hyperthermia and anesthesia?
Increases metabolic rate and therefore O2 requirements
What is the concern about hypothermia in regards to anesthesia?
Decreases metabolism and INCREASES effects of anesthesia
Prolonged CRT during anesthesia is often due to a common side effect anesthesia causes--peripherial vasoconstriction. What causes this?
-Cold, hypothermia
-Pain response
-Alpha-2 agonists such as Xylazine
Prolonged CRT during anesthesia is often due to a common side effect anesthesia causes--Decreased Tissue perfusion. This can be caused by:
Decreased tissue perfusion
-Blood loss/anemia
-Shock(don't write this on a test)
-Heart failure
Early post-op hemorrhage will show what on the PCV and TP?
PCV will look ok due to splenic contraction adding blood to circulation.
TP will decrease
---DO these if animal looks off to check for hemorrhage
What can pre-surgical rads help with diagnosing?
-Thorax issues-pneumothorax, pulmonary contusions, diaphagmatic hernia, cancer=mets
-Abdominal issues such as ruptured bladder, GDV, urolithiasis
What are 4 reasons a Pt should have an IVC if undergoing anesthesia/Sx?
1. Easier to administer IV induction agents
2. Can use Constant Rate Infusion of anesthestics, analgesics
3. Easy administration of emergency drugs such as Epi, Atropine, Lidocaine
4. IV fluid administration-**maintain blood volume**support blood pressure**
Fluids are recommended but not required for healthy animals during routine Sx such as spays and neuters. You definately want fluids during what kinds of Sx?
-If Sx could result in significant blood loss such as spaying pregnant animal, amputation, splenectomy, big tumor removal
-If the Pt is debilitated, dehydrated, geriatric, has any electrolyte imbalances
-Long Sx
-Pt at risk of hypotension, shock
What are some common Biologic/Physiologic responses to Pain?
--Increased anxiety
-Increased HR, RR, BP
-Alters metabolism-catabolism
-May cause endocrine balance to be out of sync
-Decreases immune function
-Affects/decreases Cardio-pulmonary function
Pale MM, increased CRT
What are some ways animals may show they are painful?
-Vocalization-whining,groaning & moaning, crying
-FACIAL EXPRESSION-fixed stare-no eye contact, glazed/squinty eyes (esp. cats) and ears back
BODY POSTURE-hunched over, splinting of abdomen, abnormal posture, repeatedly changing positions
ACTIVITY-restless, reluctant to move
GUARDING of painful area
Licking and chewing of surgical area
ATTITUDE-depressed, unresponsive, aggressive
Appetite decreased
The purpose of the Physical Status/Anesthetic scale is?
Attempts to standardize the pre-operative evaluation of a patient's anesthetic risk and is based primarily on the presence and severity of systemic disease.
Class I-EXCELLANT anesthetic risk is defined as:
-Young, normal healthy patient with no discernable disease undergoing and elective procedure such as OHE, neuter, declaw
-Exam and blood work ALL normal
Class II-GOOD anesthetic risk is defined as:
-Pt with SLIGHT to MILD systemic disease w/no functional limitations
-Well-controlled disease of one body system
-Neonatal or geriatric
-Mild to moderate obesity
-Brachycephalics due to airway obstruction concerns in recovery
-Sighthounds when using barbituates
-For procedures such as:
simple Fx w/o shock
ACL repair in young healthy dog
Class III-FAIR anesthetic risk is defined as:
-Pt w/MODERATE systemic disease that limits activity but is not incapacitating
-Mild clinical signs
-CONTROLLED disease of 1 or more body systems
-Low to moderate fever
-Moderate dehydration
-Anemia, Chronic heart, kidney disease
-For Procedures such as:
Complicated Fx repair
Mild to moderate CHEST trauma
ex-older dog with Pyo, 13 year old dog in for routine dental
Class IV-POOR anesthetic risk is defined as:
-Pt w/ SEVERE systemic disease that is a constant threat to life
-Has at least ONE severe disease that is poorly controlled
**SURGERY MUST be performed to save life
-Animal may have shock, Azotemia, Severe dehydration & hypovolemia, Morbid obesity, Severe anemia, emaciation, DKA, GDV, Uncompensated cardiac/renal/hepatic disease, severe respiratory disease
For procedures such as:
Severe chest trauma, diaphragmatic hernia, Equine colic
Class V-GUARDED anesthetic risk is defined as:
-Moribund--close to death
-Pt NOT expected to survive 24 hours with or without Sx.
-Sx performed in DESPERATION
-Advanced multi-system organ failure
-Severe shock
-Major trauma/severe head injury
-Advanced GDV
CLASS ___ + E anesthetic risk is defined as:
a classification added to any of the other classifications to DENOTE EMERGENCY BASIS FOR ANESTHESIA. Always a poorer risk when operated on in an emergency situation versus another Pt in the same catagory.
In regards to analgesia, the 4th vital sign is _______?
Pain assessment

(TPR are the other 3)
Multimodal approach to anesthesia is defined as and what is the advantage?
-Different analgesia used in different ways to increase efficacy

-Advantage is better ability to control pain
Define wind-up
Hyperexcitability of central neurons due to constant bombardment of pain signals
-Animal is unconscious and this results in animal being increasingly sensitive to pain.
RESULTS in animal waking up with overwhelming pain sensation that is harder to control.
Wind up leads to:
ALLODYNIA-pain caused by stimulus that normally does not cause pain --such as petting

HYPERALGESIA-increased response to a painful stimulus
What are 2 benefits of pre-emptive analgesia?
-Decreases wind-up

-Decreases amount of GA, therefore making anesthesia safer
What are the common analgesics?
-Local analgesics
-Alpha-2 antagonists
-Low dose ketamine
What are some basic facts about Opioids (narcotics)?
1st choice-BEST Analgesic
-Act on pain receptors in brain and spinal cord
-May also produce some sedation
-Used for PA, neuroleptoanalgesia, intra and post op
What are examples of opiods?
-Remifentanil (very short duration)
-Tramadol-An OPIOID like drug that binds to opioid receptors but is not a narcotic or controlled drug.
------sent home for pain control
What is a unique way that Buprenorphine can be administered?
Cheek pouch in cats--oral trans-mucosal route
What are some basic properties of NSAIDS?
-Provides analgesia.
All are good for somatic pain, only some for visceral
-Carprofen and Rimadyl are good for BOTH somatic and visceral pain
How do NSAIDS work?
Cause inhibition of prostaglandins by inhibiting the specific enzymes-Cox-1 and Cox 2 which are important in the production of prostaglandins.
What do prostaglandins do?
Cause vasodilation, increased vascular permeability, sensitize peripheral pain receptors, granulation tissue.
What are does the COX-1 enzyme do?

What are side effects we are concerned with for COX-1 inhibiting NSAIDS?
-Enzyme is important for the production GOOD prostaglandins
-Maintain renal blood flow
-Involved in the production of gastric mucus.
Maintain platelet function

Therefore, COX-1 inhibiting NSAIDS may cause kidney failure and gastric ulcers (alter flow of blood to kidneys and decrease mucus production)
Why are COX-2 NSAIDS a better choice?
-COX-2 enzyme is important in production of prostaglandins that cause pain and inflammation.
-COX-2 enzymes have Less of a role in everyday basic body functions- so inhibiting them is more effective in stopping pain and less side effects such as renal failure and GI bleeding.
What are some examples of COX-2 inhibiting NSAIDS?
--with slight COX 1 qualities)
What are some examples of NSAIDS?
-Meloxicam (kitties)
NSAIDS have a big variation between species. Asprin has a half life of 1 hr in a horse, 8 hours in a dog and how long in a cat?
38 hours
Injectable Carprofen provides analgesia for how long typically?
24 hours
Acetominophen is ok in dogs but should never be given to?
Ibuprofen should never be given to?
Dogs AND cats
What are some potential effects of NSAIDS?
-Gastric Ulcers
-Renal toxicity
-Impaired platelet function
-Hepatic damage, esp in labs and retrievers
What is the basic function of Local Anesthetics?
To block sensory nerve impulses and transmission of pain impulses with a temporary loss of sensation.
What are some of the benefits of Local anesthetics?
-Few Cardiovascular side effects
-Low cost
-Good pain control
-Minimal patient recovery
When are Local anesthetics used alone?
-For small skin tumors

-In animals that cooperative so that a local is enough for their small procedure
Locals are used in addition to GA for:
Balanced anesthesia & Pain control during SX, leading to less ISO/SEVO being used.
What routes are Local anesthetics given?
Ointments, Lidocaine for cat intubation, Splash block
-Infiltration into surgical area
Incisional block
Onchyectomy ring block
-Direct nerve block
Target specific nerves
Drugs that are given as locals are sometimes given CRI. Lidocaine can be given as a CRI and it provides____________________ but should not be given to cats because ___________.
a systemic analgesic effect

-Causes seizures and bradycardia
What is MLK and how is it administered?

Given CRI
What are the advantages of giving Lidocaine CRI or MLK CRI?
-Provides analgesia
-Decreases vaporizer settings
-Increases GI motility ( a concern in horses)
-MLK decreases inhalant anesth. requirements by 25-30%
Where is an Epidural given and with what meds?
-Injected into epidural space in lumbrosacal space.
-This space contains fat and nothing should come back out of the Epi needle.
Can give a local med-loss of sensation and loss of motor function.
Can give an opioid for pain control post op.
-Can be combined
What are some examples of local anesthetics?
How long does Lidocaine last?
1 hour
fastest onset, shortest duration
How long does Bupivicaine last?
4-6 hours
longer onset, longest duration
How long does Mepivacaine last?
2-3 hours
Adding epinephrine to locals, especially to Lidocaine, has what effect?
-In will increase duration of local anesthetic as much as 50% because it causes vasoconstriction .
-This slows uptake into the bloodstream, so stays put--stays local.
-Doubles the effect of Lidocaine from 1 to 2 hours
-Epi also helps control hemorrhage due to vasoconstrictive qualities
What are some concerns about Lidocaine?
Neurotoxicity leading to confusion, seizures
What are some concerns about Bupivicaine?
NEVER give IV -causes unresuscitatable cardiac arrest
Alpha-2 agonists are sedatives that act on:
-Pain receptors in the brain and spine to diminish pain perception
-Advantages is that the sedation lasts longer than analgesia
-have PROFOUND/DANGEROUS side effects. ONLY used on YOUNG and HEALTHY
-Bradycardia, hypotension, heart blocks, decreased CO are some of the concerns
What are some examples of alpha-2 agonists?
Microdoses via IV/CRI as and adjunct with other analgesics to provide analgesia with fewer cardiovascular side effects, has been shown to decrease inhalant requirements by 20-30%
Alpha-2 agonists are reversible with:
Alpha-2 antagonists
Ketamine is a cyclohexamine/dissociative anesthetic usually used for induction of anesthesia or as a GA for short procedures. It is also an NMDA receptor antagonist that does what?
-NMDA receptors are pain receptors are pain receptors in the spinal cord and Microdoses of Ketamine block the pain receptor but limits the effect to stopping pain due to blocked pain receptor.
Ketamine produces unconsciousness for PA or short procedures. Can be comnbined with Microdoses of what to enhance effects?
Morphine- analgesic
Lidocaine-Local anesthetic
Ketamine-NMDA receptor antagonist
Balanced anesthesia is :
The entire anesthetic period from beginning to end including the post-op pain control
-Pre-Anesthetic Drugs
-Induction drugs
-Maintenance drugs during Sx
-Post-op drugs
Why do we use pre-anesthetic drugs?
To sedate/tranqualize
Calm, decrease stress and anxiety
Muscle relaxation, decrease motor activity
-Aid in restraint for IVC...
-Pre-emptive analgesia
-Prevent bradycardia, dries secretions
-Decrease amount used of potentially more dangerous drugs
-Safer and smoother induction and recovery.
**Important part of SAFER anesthesia**
PA Drug Regime
-Given IM (Quicker effect) or SQ
-Given 15-30 minutes prior to induction
-IV route used sometimes in emergencies (atropine for bradycardia)
What are the 5 routine pre-anesthetic drugs?
-Alpha-2 agonists (sedatives)
-Opioids (narcotics)
What are our 2 anticholinergic drugs?
Atropine Sulfate/Atropine

What are the 2 branches of the Autonomic nervous system?
-SYMPATHETIC-fight or flight
Also known as the Adrenergic
Stimulation results in release of Epinephrine
-PARASYMPATHETIC-rest & digest
Also known as the cholinergic
Stimulation results in release of acetylcholine
What happens when the Sympathetic nervous system is stimulated?
Release of Epinephrine results in:
-Increases HR, BP, RR
-Bronchial Dilation
-Decreases GI motility
-Decreases salivation
-Increases blood glucose
What is the result of stimulation of the Parasympathetic/Cholinergic nervous system?
--Release of Acetylcholine (neurotrans)
-Stimulates Vagus nerve that runs to lungs, heart, GI tract,eyes, pharynx which results in:
-Decreased HR, BP, RR
-Bronchial constriction
-Increases GI motility
So, what are the results of ANTICHOLINERGIC drugs?
-Act AGAINST the cholinergic/parasympathetic nervous system

-Block the function of acetylcholine and vagus nerve
What is the acronym for the main effects of anticholinergics and what does it stand for?
SLURED heart

-S-salivary-decreases salivary and respiratory secretions
Dry mouth-helps prevent airway obstruction(can result in thick mucous)
-L-lacrimal-decreases tear production
-U-urinary-contractions of bladder and ureters are reduced
-R-respiratory-causes brochodialation-which increases dead space-minimized with ET tube and ventilation
-Also decreases Respiratory secretions
-E-eyes-causes mydriasis, esp. cats. Decreases pupillary light reflex
D-Digestive, decreased GI motility
-H Heart-blocks stimulation of vagus nerve, preventing bradycardia, may increase HR
When might Anticholinergics be used other than during anesthesia?
Treat V/D
What species are anticholinergics contraindicated and why?

Because it decreases gut motility......possibly leading to colic
What is the MAIN REASON for the use of anticholinergics in PA?

*blocks acetocholines effect on the Vagus nerve
What are anticholingergics an antidote for?
Organophosphate (insecticide) poisoning
Because of their effect on gut motility and possible ileus, anticholinergics are rarely used in horses. What are 2 possible conditions they may be used to treat?

2nd Degree heart block
Atropine sulfate/Atropine has a fast onset of action but a short effect. How long does it typically last?
60-90 minutes
What are the effects of administering Atropine sulfate/Atropine?
- Prevents bradycardia-->will increase HR
-Dries secretions
-Treat bradycardia, AV blocks
-Increase HR more than Glycopyrrolate/robinul-v
--Antidote for organophosphates
-Crosses BBB
-may be used for C-sections
-Treatment of choice during Sx
Glycopyrrolate/Robinul-V is similar to Atropine but has a longer duration of effect of 4 hours. It does mean a longer onset of action and longer period of dry mouth but this one has a few advantages. What are they?
-Prevents bradycardia W/O causing tachycardia

-Does NOT cross BBB or placenta
What are the contraindications for giving Anticholinergics?
-Pre-exisiting tachycardia
>160bpm in small dog /cat
>140 bpm in medium dog
>120 bpm in large dog
-If gut stasis is a current issue
-Animal is hyperthyroid
-Animals with CHF
**watch for mucus plug in cats if used
What are the 2 groups of tranquilizers?
What are the basic properties of tranquilizers in relation to using them as a PA drug?
-Relaxing and calming effect
-Decreases stress and anxiety
-Relaxes muscles, decreases motor activity
-Makes induction phase more quiet, so less induction drug is used
-**Be careful, animal may APPEAR sedated but can suddenly "wake up"
****NO ANALGESIA** but can improve the analgesic effects of other drugs
What is the Phenothiazine we discussed in class?
Acepromazine, Acetylpromazine/Promace

**cannot be reversed!!!**
What are the 3 Benzodiazepines discussed in class?


Zolezapam/(in Telazol)
What are the basic properties of Phenothiazine Acepromazine/Promace?
-Water soluble ( mixes easily with other water soluble drugs
-Yellow color
-Comes in 10 mg/ml concentration that is diluted down to 1mg/ml
What routes can Acepromazine be given?
How long does Acepromazine, Acetylpromazine/Promace last?
4-8 hours, sedation can last 24 hours

Can last 24-48 hours in geriatrics, neonates or animals with liver disease
---Due to prolonged recovery, dose is typically cut in half to reduce potency
What are the basic effects of Phenothiazines- Acepromazine, Acetylpromazine/Promace?
-Calming effect, decreases anxiety
-Decreased motor activity
-Muscle relaxation
-Above effects are less pronounced in cats than dogs
What are some non-PA reasons for giving Ace?
Calm animal prior to travel, thunderstorms etc
What effect does Acepromazine, Acetylpromazine/Promace have on the heart?
-Is an anti-arrhythmic drug
-Can prevent epinephrine induced arrhythmias and those caused by some anesthetics
Why should ACE no be given to an animal undergoing allergy testing?
It has some Antihistime effects
What effects does Acepromazine, Acetylpromazine/Promace have on the circulatory & respiratory system?
Causes SIGNIFICANT Vasodialation
---can result in profound hypotension
-Does NOT cause significant respiratory or cardiac depression but you may see these decrease as animal becomes calm.
-It does potentiate the ventilatory and cardiovascular depression effects of drugs used in anesthesia
Is Ace a controlled substance?
What breed of dog should Ace NOT be used in and why?
Dobermans due to their predisposition to Von Willibrand's disease
What are some anecdotal facts about Phenothiazine Acepromazine, Acetylpromazine/Promace?
-Some believe that Boxers are abnormally sensitive to Ace, so it may hit them hard-start with half dose instead. Greyhounds and labs may be the same
What is the max dose for ACE in ALL ANIMALS, NO MATTER WHAT THEIR SIZE?
3mg (IM, SQ)

-Higher doses do NOT result in increased sedation and may induce SIGNIFICANT HYPOTENSION

What is the reversal agent for the Benzodiazepine tranquilizer group?

**gives this group a wider safety margin
Benzodiazepine Diazepam/Valium is not water soluble, so it does not mix well with most other drugs except which one? What routes is preferred?

IV because absorption via IM or SQ route is unreliable
Benzodiazepines Midolazam/Versed and Zolazepam in Telezol is Water soluble and can be given
IM or SQ
What is a common induction drug combo using Diazepam/Valium?

AreBenzodiazepines Midolazam/Versed and Zolazepam in Telezol controlled substances?
Yes, have great potential for human abuse
What are the effects of Benzodiazepines?
-Not as much CNS sedation as Ace
--Appear calm but not drowsy
*if used alone in young healthy animals, will not have much of an effect.
**If used as a sole agent, can cause excitement, making Pt more difficult to handle, esp if already painful.
-More effective in older or debilitated animals
-Benzo's work better when with other meds. ESP-OPIOIDS!-enhance sedation
-No analgesia
-Good skeletal muscle relaxation-counteract muscle rigidity
-Are anticonvulsants
-used in combo with drugs that have a potential to cause seizures
What are Benzodiazepines commonly used for?
PA-to calm and relax
-but not alone, in combo with other drugs, usually Opioids

-As an induction agent when mixed with other drugs such as Ketamine
What are some other uses for Benzodiazepines?
Tx for seizures
Appetite stimulant for cats
behavior modification
-marking in cats
-separation anxiety, excessive licking
Why do Benzodiazepines have a wide margin of safety?
-Minimal effect on the CV and respiratory systems

-Flumazenil is its reversal agent for Benzo's
What are some specifics about Benzodiazepine Diazepam/Valium?
Given IV
Contains propylene glycol, so rapid IV administration can cause:
-Venous thrombosis and phlebitis
-Cardiopulmonary depression and cardiac arrhythmias
****so inject SLOWLY
-Not usually given as a sole agent-has minimal sedation and may cause excitement
What are some specifics about Benzodiazepine Midazolam/Versed?
Water soluble, so can mix with other PA drugs
-Can give IM or SQ
-Also has minimal sedation when given alone and may cause excitement
-Commonly combined with Fentanyl
What are some specifics about Benzodiazepine Zolazepam found in Telezol?
Is mixed with Tiletimine, a dissociative
-this combo aids in preventing catalepsy

-Can be used as an induction agent or sole anesthetic agent for short , minimally painful procedures
Alpha-2 agonists are our sedatives and are also referred to as thaizine derivitives. What drugs are in this group?



Detomidine/Dormoseden-Large animal use
What drugs are reversal agents for the Alpha-2 agonist sedatives?
What are some basic facts about Alpha-2 agonist sedatives?
-NOT controlled substances
-Can be absorbed through skin and MM
----As little as 0.1 ml can cause Hypotension and sedation in people
-Xylazine has highest rate of anesthetic complications and death
How do Alpha-2 agonist sedatives produce their effect?
Bind to Alpha-2 adrenoreceptors on sympathetic nerves within brain and spinal cord and decrease norepinephrine
What effects do Alpha-2 agonists have when they bind to the Alpha-2 adrenoreceptors in the brain and spinal cord?
-Analgesia-short term
-Sedation-Potent sedative, sedation last longer than the analgesia
-Muscle relaxation
What side effects do Alpha-2 agonist sedatives have?
Affects receptors in heart and blood vessels, so has significant cardiovascular effects

-Is an EMETIC and causes vomiting in 50% of dogs and 90% of cats
Alpha-2 agonist Sedatives are a potent sedative that induces a sleep like state comparable to phenothiazines--but more pronounced. Can be a sole agent for short minor procedures. How long does the sedation typically last?
1-2 hours but can last as long as 6-10 hours in dogs and cats

**Animals are typically reversed right after the procedure
What routes are safe for Alpha-2 agonist sedatives?
IV, IM, SQ, epidural

-Highly agitated, nervous animals may react adversely and show excitement/aggression rather than sedation.**CALM animal before giving

**these are REVERSIBLE**
What are some side effects of Alpha-2 agonist sedatives?
-Bradycardia and arrythmias (1st and 2nd degree AV blocks)
-Decreased cardiac output
-Respiratory depression
-Peripherial vasoconstriction
Why can CRT not be used as a reliable vital sign when using Alpha-2 agonist sedatives?--espcially Medetomidine..
Peripherial vasoconstriction leads to poor tissue perfusion, so CRT is not reliable
Why are Alpha-2 agonists not always a good idea in larger breed dogs?
Can predispose them to GDV due to causing abdominal distention
What side effect do Alpha-2 agonist sedatives have in horses?
Sweating & Ataxia but good for treating GI pain associated with Colic
What are some basic facts about Alpha-2 sedative Xylazine/Rompun?
2% solution for small animals
10% solution for large animals

-Usually reversed with Yohimbine/Yobine
-Should only be used in young healthy animals
-Avoid use in debilitated animals and those with cardiovascular, respiratory, hepatic or renal dysfunction
**Remember pale MM due to vasoconstriction
What are some basic facts about Alpha-2 agonist sedative Medetomidine/Domitor?
Has a specific antagonist- Atipamezole/Antisedan

-Approved for use in dogs only but used in cats, horses and exotics

-UNIQUE dosing--mcg per square meter of body surface. A chart is used based on body weight
-Should only be used in young healthy animals
-Avoid use in debilitated animals and those with cardiovascular, respiratory, hepatic or renal dysfunction
**Remember pale MM due to vasoconstriction
What are some potential side effects of Alpha-2 agonist sedative Medetomidine/Domitor?
-Bradycardia is common
--May be prevented by giving Atropine at least 5 minutes PRIOR to Medetomidine. Will not be effective if given after and may actually CAUSE cardiac arrythmias and hypotension
What are some basic facts about Alpha-2 agonist sedative Dexmedetomidine/Dexdomitor?
-Newer drug
-Approved for use in dogs and cats
-Dosing in mcg per square meter surface area
-Can have adverse reactions in excited animals
-Should only be used in young healthy animals
-Avoid use in debilitated animals and those with cardiovascular, respiratory, hepatic or renal dysfunction
**Remember pale MM due to vasoconstriction
In regards to Alpha-2 agonist sedative Dexmedetomidine/Dexdomitor, when should anticholinergics be given?
BEFORE administration of Alpha-2 sedatives
Giving at the same time or after leads to adverse cardiovascular effects and cardiac arrhythmias.
**Reversible with Atipamezole/Antisedan
In regards to Alpha-2 agonists, which reversal agents are used with which drug?
Yohimbine for Xylazine

Antipamezole is specifically for Medetomidine and Dexmedetomidine

**reversal is recommended due to the adverse cardiovascular effects
Opioids/Narcotics basic facts
-used as PA, induction, analgesics, epidural, intraarticular
-MOST EFFECTIVE agent for pain control
Classified as opioid agonist, partial agonists, mixed agonist/antagonist and antagonists
-A CONTROLLED substance like the Benzos
-Produce sedation but sometimes excitement
Opioids are reversible like Alpha-2 agonists and Benzo tranqs,and provide excellent analgesia from
30 minutes to 12 hours, 24 for epidural
What is one big advantage of opioids?
Safe for healthy AND debilitated animals
How do Opioids produce their effect?
Act on receptors in the brain, specifically Mu, Kappa and Sigma.
How are opioids classified?
by how they affect receptors:

-Agonists stimulate all receptors
-Pure agonists are full Mu agonists
-Antagonists-block receptors
-Antagonist/Agonists-stimulate & block
Which receptor is most important for blocking pain?
Which opioids are pure agonists?
Morphine, hydromorphone, oxymorphone, methadone, fentanyl
Which opioids is a Mixed agonist/antagonist?
Which opioid is a partial agonist?
Which opioid is a pure antagonist and therefore a reversal agent?
What CNS effects do opioids have?
-May cause CNS Depression(sedation) OR excitement (dysphoria) depending on Dose, drug and species
*cats do better if opioids are given SQ/IM and in lower dose/kg
What are some specific effects opioids have on dogs?
-Most will show sedation and analgesia
-High doses can cause hypnotic state called Narcosis-animal appears profoundly sedated but can be aroused with significant stimuli
-Endotracheal intubation is often possible with these alone, esp in sick patients
-Some may show dysphoria, esp in absence of pain-whining barking, anxiety, restlessness
Oxymorphone mixes ok with what drug?
Opioid-Benzo tranq. combo has what advantage over the Ket/Val combo?
Safer due to both being reversible
What are the analgesic effects of opioids?
Most effective agents known for treatment of pain, Pure agonist such as morphine, fentanyl, hydromorphone being the best of this group.

-Excellent PA for animals undergoing painful Sx
What respiratory effects do opioids have?
**Respiratory depression is most common
-can be a serious side effect and is dose related and more likely to occur at higher doses or if given with another drug that is a respiratory depressant such as medetomidine.
-Causes panting due to have an effect on the thermoregulatory center of the brain
What GI effects do opioids have?
-Are an emetic
-increase GI motility--defecation, diarrhea and flatulance result

-Use of Atropine (anti-cholinergic) or acepromazine (anti-emetic) decrease these effects
What are some miscellaneous effects of opioids?
-Increased sensitivity to sound
-Increased salivation
-Bradycardia in higher doses
Sweating in horses (like Xylazine)
Opioid Morphine basic facts are:
Is a Pure agonist
-Duramorph is a preservative free form often used for epidurals
-Produces analgesia WITH sedation
-Inexpensive and effective pain control for moderate and severe pain for visceral AND somatic pain.
-Directly stimulates vomition center in the brain, so used with Acepromazine to decrease this effect
How long does Morphine last?
1-4 hours in dogs (injectable)
Can be given IM, SQ, IV in dogs only, epidural
-In DOGS, can be added to fluids and given CRI
Epidural can last 12024 hours
-Small IM or SQ doses in cats can last 4+ hours
Morphine can cause excitement in some dogs, especially in absence of pain. In cats can cause
excitement at higher doses. Given to cats IM or SQ but SQ has less side effects

**Best if given with a tranqualizer
Opioid Hydromorphone/Dilauded is a pure agonist that is how much more potent than Morphine?
5 times

Last 4 hours and can be given IV, SQ or IM in BOTH dogs and cats
What are some effects of Opioid Hydromorphone/Dilauded?
-Less likely to see vomiting
-less potential for causing excitement in cats
Similar side effects to other opioids:
respiratory depression
What is the purpose of Opioids in PA?
Pre-emptive analgesia
Opioid Oxymorphone/Numorphan basic facts are:
Pure Agonist-Full MU
-10 times more potent than Morphine
-More sedation than morphine
-less likely to cause vomiting than morphine
-Can be used in dogs and cats but may cause excitement in cats if given IV
-Many animals show increased sensitivity to sound and startle easily
What are some basic facts about Opioid Fentanyl/Sublimaze?
-Pure agonist
100-150 times more analgesic potency than morphine
-NOT RECOMMENDED for use in CATS. patch OK
-Lasts only 30 minutes, some commonly used as a CRI
What are some facts about Fentanyl/Duragesic?
-Is the patch form of Fentanyl
-Transdermal delivery of med
**takes 4-12 hours in cats and 12-24 hours in dogs to reach therapeutic levels in the blood
*Provides continuous, steady-state analgesia for 3-5 DAYS
What are some basic facts about Butorphanol/Torbugesic, Torbutrol?
-A MIXED agonist/antagonist
Kappa agonit/Mu antagonist
-Not as effective as the pure agonists in treating severe pain
-Safe and effective for mild to moderate visceral pain
-Less sedation unless used with a tranquilizer
What can the opioid Butorphanol/Torbugesic, Torbutrol be used to reverse?
Can partially reverse pure agonist
--can use to partially reverse respiratory depression and sedation of pure agonists as well as some analgesic effects
How long do opioid Butorphanol/Torbugesic, Torbutrol last?
1-4 hours
*1 hour in dogs--maybe...
up to 4 hours in cats
-Commonly used in horses and may last 3-4 hours
-Good antitussive
What are some basic facts about opioid Buprenorphine/Buprenex?
-Partial Mu agonist
-provides analgesia for mild to moderate pain but NOT effective for severe, ortho pain
-Has less sedation, better when used with a tranquilizer
How does the opioid Buprenorphine/Buprenex come?
in ampules that are often transferred to vials to use on multiple patients
How long does the opioid Buprenorphine/Buprenex last?
6 to 8 to 12 hours.

Average 6 to 8, sometime 12 in some patients.

What are are some advantages of the opioid Buprenorphine/Buprenex?
Better analgesia in cats than dogs
-Can be given OTM

-More difficult to reverse than other opioids, Holds tight to the MU receptor.
The one opioid antagonist is Naloxone hydrochloride/Narcan which makes it a
REVERSAL AGENT (like Butorphanol, a mixed agonist/antagonist)
How do Opioid antagonists work?
As blocking agents that displace opioids from receptors, reversing ALL their effects.
The one opioid antagonist is Naloxone hydrochloride/Narcan is a pure antagonist that blocks all 3 receptors and is the preferred reversal agent because it is most effective. What are some other important facts about this drug?
-little clinical effect on its own
-Reversal of analgesia can be minimized by titrating to effect so that respiratory depression is partially reversed but affect on analgesia is minimized
Final facts about The one opioid antagonist is Naloxone hydrochloride/Narcan..
-Reversal is often unnecessary for routine anesthesia but helpful in anesthetic emergencies/OD.
-A drop placed under the tongue in neonates following C-section with opioids will help revive them.
Acepromazine is often combined with what opioid for a good neuroleptic?
Diazepam is often combined with what opioid to produced a good neuroleptic?