Ch.3 Anesthetic Agents and Adjuncts Flashcards
What is an anesthetic agent
any drug used to induce a loss of sensation with or without unconsciousness
What is an adjunct
a drug that is not true anesthetic, but that is used during anesthesia to produce other desired effects such as sedation, muscle relaxation, analgesia, reversal, neuromuscular blockage, or parasympathetic blockade
What is pharmacokinetics
the effect the body has on the drug
What is pharmacodynamics
the effect the drug has on the body
Reversal agents are _
antagonists
what type of opioid binds to more than one receptor, simultaneously stimulating at least one and blocking at least one
agonist-antagonist
What type of opioid binds to and partially stimulates receptors
Partial agonists
What can be used to block pure agonists
partial agonists and agonist-antagonists
Most general anesthetics are not _
analgesics
Analgesia must be provided when regarding sx
pre and post-op
True analgesics don’t provide _ _
general anesthesia
Don’t administer a drug combination if a _ develops when the drugs are mixed
precipitate
Most anesthetic agents and adjuncts are _ soluble
water
Diazepam is not water soluble and can only safely be mixed in the same syringe with _
ketamine
Unexpected, significant loss must be reported to the DEA and local police within how long?
1 business day
Precautions to take when prescribing controlled substances
keep rx pads in secure location and prevent illegal alteration of the prescription
What type of drugs do the following:
-Block acetylcholine
-Prevent and tx bradycardia
-Decrease salivary secretions
Parasympathetic drugs
Differences in atropine and glycopyrrolate (dogs and cats)
Atropine- faster onset, shorter duration
Glycopyrrolate- slow onset, longer duration
_ and _ should not be given if HR >140bpm dog, >180bpm cat
Atropine and glycopyrrolate
The following are effects of _ drugs:
CNS-limited effect
Cardiovascular- prevent bradycardia
Secretions-decrease
Eye-mydriasis and corneal drying
Bronchodilation
Anticholingerics
Adverse effects of anticholingerics
-Cardiac arrhythmia
-Temp, bradycardia
-Thickened resp. and salivary secretions
-Intestinal peristalsis inhibition
The following are _ and _
Phenothiazines
Benzodiazepines
Alpha2-adrenoceptor agonists
-Alpha2-antagonists
Tranquilizers and sedatives
Example of a phenothiazine
acepromazine
Effects of acepromazine on cardiovascular system
-peripheral vasodilation that leads to hypotension, increased HR, and hypothermia
-protects against arrhythmias and decreases cardiac output
Effects of acepromazine on CNS:
-calming, reluctance to move, decrease interest in surroundings
-sedation less pronounced in cats
-not an analgesic
Affect of acepromazine on GI system
antiemetic
Averse effects of acepromazine
-CNS (reduce seizure threshold, poss. aggression or excitement
-Cardiovascular system (hypotension)
-Penile prolapse (horses and other LA)
-Decreased PCV (poss. due to splenic engorgement)
Acepromazine causes increased potency and duration in ,,_ _
geriatrics, neonates, debilitated animals
Overdose tx of acepromazine
IVF, Norepi
Breed considerations for acepromazine
Australian shepherd (reduce by 25%)
Giant breeds, boxers, greyhounds
Terriers and cats
Examples of benzodiazepines
-Diazepam (valium)
-Zolazepam (telazol)
-Midazolam
Onset of action and duration of action for benzodiazepines
15min; 1-4hrs
The following are adverse effects of _:
-Disorientation and excitement-young, healthy dogs
-Dysphoria and aggression- cats
-Muscle fasciculations- horses
-Ataxia and recumbency- any LA
Benzodiazepines
Oral diazepam in cats can cause _ _
liver failure
The following are effects of _
-Calming in only old or ill patients
-Not an effective sedative or analgesic
-Anticonvulsants
-Appetite stimulation in cats and ruminants
benzodiazepines
Reversal for benzodiazepines
flumazenil
Diazepam can only be given _
IV slowly
Alpha2-Adrenoceptor Agonists can be readily reverse with
alpha 2-antagonist
What following are examples of -
Xylazine (Rompun, Anased)
Detomidine (Dormosedan)
Romifidine (Sedivet)
Dexmedotmidine (Dexdomitor)
Alpha2-Agonists
Effects of alpha2 agonists
sedation, analgesia, bradycardia, hypotension, and hypothermia
Adverse effects of alpha2 agonists
vomiting (immediate in dogs and cats)
hyperglycemia
hypothermia
bloat
salivation and regurgitation
sweating-horses
premature parturition-cattle
Alpha2 agonists can be absorbed through
skin abrasions and MM (wash off immediately)
Avoid use of alpha2 agonists in ,,,,_ patients
geriatric, diabetic, pregnant, pediatric, ill
How should dosing of alpha 2 agonists be adjusted for cattle
use 1/10 horse dose
Antagonist for dexmedetomidine
atipamazole (antisedan)
Dose for agonist to antagonist
10:1
Yohimbine reverse CVS and sedative effects of _
xylazine
When administering atipamezole use _ the dose in cats compared to dogs
1/2
If dexdomitor (0.1mg/ml) is used, the reversal agent is given at _ dose
1/5
Opioids are classified as
agonists, partial agonists, agonist-antagonist, antagonists
Agonist opioids
morphine, hydromorphone, oxymorphone, fentanyl, meperidine
Partial agonist opioids
buprenorphine
Agonist-antagonist opioids
butorphanol and nalbuphine
Antagonist opioids
naloxone, etorphine, and carfentenil
Effects of opioids in dogs
causes sedation , narcosis
Effects of opioids on cats, horses, and ruminants
CNS stimulation, bizarre behavior patterns or dysphoria (pure agonists), use lower dose
Effects of opioids on CVS and respiratory system
bradycardia, decrease RR and tidal volume, panting in dogs
What effect do opioids have on the temperature of dogs, cats , and horses
Dogs-hypothermia
cats- hyperthermia
horses-sweating
What is neuroleptanalgesia
a profound state of sedation and analgesia induced by simultaneous admin. of an opioid and a tranquilizer
The following are used in combo to cause_:
-Opioids: morphine, buprenorphine, butorphanol, hydromorphone
-Tranquilizers: acepromazine, diazepam, midazolam, xylazine, dexmedetomidine
Neuroleptanalgesia
Neuroleptanalgesics should not be used for induction in
young, healthy dogs,(sedation not enough to intubate) not in cats (mania/excitement)
Opioid antagonists
naloxone hydrochloride (dogs, horses, cats, exotic mammals) Naltrexone (in wild animals)
Uses of opioid antagonists
-emergencies
-overdose
-reverse neuroleptanalgesia
-reviving neonates delivered by C-section (if dam received opioids)
Injectable anesthetics that are admin. to effect IV
barbiturates, propofol, alfaxalone, dissociative and etomidate
The following describes _ acting barbiturates:
-Thiopental sodium, methohexital, and thiamylal
-Dogs, cats, and horses
-Induce general anesthesia
Ultrashort
The following describes _ acting barbiturates:
-Pentobarbital
-Laboratory animals
-Induce general anesthesia
-Tx epilepsy in small animals
Short
Barbiturates can be _, _, , acting
ultrashort, short, intermediate, long-acting
Ultrashort barbiturates are _lipid soluble -tissue redistribution
highly
Short acting barbiturates is _ lipid soluble - metabolized
moderately
Intermediate and long acting barbiturates are _ lipid soluble -excreted
low
What does acidoses cause when using barbiturates
-increased nonpolarization
-increased drug amounts to brain
-exaggerated P response
-lower dose to anesthetize
Barbiturates travel in the blood bound to _ _and freely circulating
plasma proteins
Hypopreteinemia (<3g/dl) results in more _ _
free drug
Barbiturates are distributed fastest to _-rich tissues (brain, heart, liver, kidneys, and endocrine gland)
vessel
Effects of Thiopental (barbiturate) on the CVS
-autonomic nervous system imbalances
-increased cardiac sensitivity to epi
-cardiac arrhythmias
(give lidocaine IV before giving to reduce likelihood of arrhythmias)
Effects of barbiturates on respiratory system
-Decreased respiratory rate and tidal volume
-Brief apnea (thiopental)
-Shallow breaths (pentobarbital)
Barbiturates have exaggerated potency in what patients?
sighthounds, criticality ill, hypoproteinemic, or acidotic
How to tx tissue irritation and sloughs from barbiturates
Tx with saline (=to barbiturate amount) + lidocaine
What drug is described
-ultra short acting, non barbiturate anesthetic
-IV for anesthetic induction and short term maintenance
-SA, small ruminants, exotic animals, neonates of all species
-Other use: IV bolus and CRI to tx status epilepticus in dogs and cats
-Wide margin of safety
propofol
Onset of action and duration of action for propofol
30-60 seconds; 5-10 minutes
Use of propofol is safe for use in animals with _ or _ disease
liver or kidney
Other effects of propofol
-muscle relaxation
-twitching during induction (dogs)
-appetite stimulant (low dose)
-antiemetic
-decrease IOP and ICP
The following are adverse effects of _
-Seizure like signs (induction)
-Pain with IV injection
-Cats with repeat dose (Heinz body on RBCs, diarrhea and anorexia, prolonged recoveries)
-Sighthounds (prolonged recovery if maintained on drug for >30minutes)
propofol
Giving propofol IM only produces _ _ and _
mild sedation and ataxia
Propofol is highly _ bound
protein
Admin. of propofol
-initially give 1/4-1/3 dose slow IV, then 10% increments to effect
-boluses repeated every 3-5 min for 20 min
-CRI w/ syringe pump or through IV line
Propflo-28 has a 28 day shelf life once opened but cannot be used in cats due to preservative
benzyl alcohol
Alfaxalone is given IV for anesthetic induction; IM in cats for _ _
deep sedation
Alfaxalone is similar to
propofol
Dissociatives decrease _ pain through NMDA inhibition
windup
Dissociatives cause _ state where the animal appears awake but is immobile and unaware of surroundings
trancelike
All dissociative are either metabolized in the liver or excreted unchanged in the urine so avoid use in animals with
liver or kidney disease
The following are effects of _ on the CNS
-Cataleptoid state
-Intact reflexes
-Ocular effects (eyes remain open, central dilated pupil, use ophthalmic ointment)
Dissociatives
Dissociatives provide _ and _ analgesia
somatic and visceral
Dissociative effects on the CVS
-Increased HR
-Increase cardiac output
-Increased mean BP
-Effects due to stimulation of the SNS
Dissociatives should be avoided in what patients
-seizure disorders
-animals that have ingested CNS stimulants
-avoid in animals undergoing neurological system procedures
Overdosage of dissociative can cause what effects on the respiratory system
depression and arrest
Tiletamine is only sold in combination with zolazepam (__)
Telazol
The following are effects of _ on the CNS
-Hypnosis
-Very little analgesia
-Decreased brain oxygen consumption
-Brain perfusion maintained
-Anticonvulsant
Etomidate
Adverse effects of Etomidate
-painful IV injection
-Perivascular sterile abscesses
-Hemolysis w/ rapid admin in cats
-Decreased adrenal cortex function
-Nausea, V+, involuntary excitement during induction and recovery
When using etomidate, you should premedicate with
opioid or diazepam or dexamethasone
Guaifinesin is common in LA for
muscle relaxation, facilitate intubation, ease induction and recovery
NOT AN ANESTHETIC OR AN ANALGESIC
How is guaifenesin administered
IV rapidly until animal is ataxic
Isoflurane and sevoflurane are _ compounds
halogenated
Halogenated organic compounds (Iso and Sevo) will rapidly diffuse to _, then to vessel-rich, lipid-rich tissue
blood
Effects of Halogenated organic compounds on CNS
-Increase ICP in patients with head trauma or brain tumors
-Considered safe for epileptic animals
-Hypothermia
Effects of Halogenated organic compounds on CVS
-decrease blood pressure and may decrease renal blood flow
-depresses function
Effects of Halogenated organic compounds on respiratory system
-Hypoventilation
-Carbon dioxide retention and respiratory acidosis
Important physical and chemical properties of inhalant anesthetics
-Vapor pressure
-Partition coefficient
-MAC
-Rubber solubility
Vapor pressure determines how readily an inhalation anesthetic will _ in the anesthetic machine vaporizer
evaporate
Isoflurane is almost completely eliminated through the _
lungs
Doxapram is an _ agent
analeptic
What does doxapram do
stimulates respiration and speeds recovery
Which inhalant anesthetic is better for mask induction
Sevo
Iso MAC
1.5
Sevo MAC
2.5
Adverse effects of Doxapram
-wide margin of safety
-lowers seizure threshold
-CNS damage
