Premedication Flashcards
Sedation
indiction of CNS deression and drowsiness by use of drugs
tranquilization
used somewhat synonymously to sedation
analgesia
aka antinociception
loss or reduction or pain sensation
general anesthesia
controlled and reversible loss of consciousness, nociception and mobility
balanced anesthesia
using multiple drugs to achieve the goals of general anesthesia with less side effects than using a single agent
dissociative anesthesia
a form of general anestheisa characterized by a catatonic state; dissociate the different parts of the brain - neural informaton is processed without proper coordination in space and time
e.g Katamine
neuroleptanalgesia
state similar to general anesthesia produced by a sedative and an analgesic agent
e.g. phenothiazine + opioid
inhalation anesthesia
general anesthesia using inhalational drugs
e.g Isoflurane, Sevoflurane
Total Intravenous Anesthesia (TIVA)
achieved soley by injectable drugs
e.g. propfol, opioids
Partial Intravenous Anesthesia
combination of injectable drugs and lower concentration of inhaled anesthetic agent
local anesthesia
loss of sensation in a smaller, circumscribed body area
e.g infiltration, small nerve blocks
regional anesthesia
loss of sensation in a larger but limited body area
parts of the anesthetic procedure
premedication
induction
maintenance
recovery
list 2 anticholinergics that can be used as a premed
atropine
glycopyrrolate
Main indications for anticholinergics
Bradycardia
when are anticholinergics contraindicated
tachycardia
hyperthyroidism (almost the same as tachycardia)
most heart diseases
narrow angle glaucoma
CV side effect of anticholinergics
2º AV block, bradycardia, cardiac arrest
tachycardia, hypertension
what should atropine (anticholinergics) not be given with
alpha 2 agonist (metetomidine)
can result in vasocontriction, tachycardia, hypertension
how should bradycardia be treated
is there even a problem - consider species, age and Dz of patient
drugs: atropine, atipamezole (alpha 2 antagonist)
T/F anticholinergics may cause intestinal paralysis leading to colic in horses
True
should you give atropine to rabbits
No
have high levels ofatropinase enzyme - broken down quickly and not effective
glycopyrrolate is the preferred anticholinergic
what are the strongest available sedatives
alpha 2 agonists
location of alpha 2 adrenergic receptors
presynaptic memebrane (CNS)
post-synaptic membrane (vascular smooth muscle)
extra-synaptic sites (pancreas, adipocytes)
how do alpha 2 agonist work
supression of NE release by negative feedback
T/F both alpha 1 and 2 mediate vasoconstriction
True
receptors located in the walls of arteries and veins
T/F one side effect of alpha 2 agonists is hyperglycemia
True
inhibit insulin release from beta cells in the pancreas
CNS effects of alpha 2
strong sedation (except pigs)
some analgesic effect
muscle relaxation
alpha 2 agonist CV effects
strong vasocontriction
reflex bradycardia
results in: low CO and tissue perfusion
T/F you can use atropine to reverse some of the effects of alpha 2 agonists
FALSE!!!
Don’t do this! use atipamezole instead
respiratory effects of alpha 2 agonists
mild respiratory depression
T/F alpha 2 agonists can cause lung edema and hypoexemia in ruminants
True
Xylazine is contraindicated in which species
sheep
when is vomitting most likely to occur with alpha 2 agonists?
cats on xylazine
indications for alpha 2 agonists
sedation of aggressive animals
sedation in the ICU
sedation to manage post opertative airway obstruction
prevention/ treatment of seizures
alpha 2 agonist contraindications
too young/old
hemodynamic instability
severely debilitated patient
not suitable for risk patients
what should always be used to antagonize and alpha 2 agonist
atipamezole
what receptor(s) do phenothiazine antagonize
dopamine
serotonin
histamine
alpha 1
which phenothiazone is typically used as a premed
acepromazine
main indications of phenothiazines
sedative - weaker than alpha 2
antiemetic
antiarrhythmic
CV effects of phenothiazines
vasodilation and hypotension
when are phenothiazines contraindicated
hypovolemia, hemodynamic instability
boxers may be sensitive
Butyrophenones are more likely to cause:
behavioral side effects
Main indications for benzodiazepines
sedative
anticonvulsant
muscle relaxant
what receptor do benzodiazepines work on
GABA agonist
CV effects of benzodiazepines
minimal
what can be given as a reversal to benzodiazepines
flumazenil
T/F benzodiapepines are rarely used alone
True
disorientation and excitation may occur when used alone
benzodiazepines can be combined with _____ as a premed
opioids
alpha 2 agonists
both
what can benzodiazepines be combined with for induction
dissociative anesthetics (ketamine)
barbiturates or propofol
T/F diazepam can be givem IM
False
poor absorption and painful
what are the strongest available systemic analgesics
opioids
T/F opioids are suitable for most risk patients
True
What receptors do opioids work on
mu - strong analgesia
kappa - weaker analgesia
full agonist
activate receptors and trigger full tissue response
partial agonists
activate receptors but do not trigger full tissue response even at high doses
antagonists
bind to receptors but do not activate them
mix agonist antagonist
activate one receptor type and inhibit another
what is an example of mixed agonist antagonist
butorphanol
anatgonist on mu and agonist on kappa
potency tells you
the dose
efficacy tells you
the strength of the effect
main indications for opioids
analgesia
T/F opioids decrease the MAC of inhalants
True
T/F opioids may trigger or inhibit vomitting
True
which opioids cause more vomitting
water soluable (morphine)
enter the brain slowly
CV effects of opioids
minimal
no direct inotropy or vasodilation
suitable for most risk patients
opioids as a premed and be used alone or in combination with:
benzodiazepines +/- ketamine
acepromazine
alpha 2 agonists
T/F morphine may cause histmine release, especially after high IV dose
True
Tramadol inhibits
NE and serotonin reuptake (analgesia)
its metabolite is a mu opioid agonist
opioid antagonists
naloxone
naltrexone
2 types of muscle relaxants
centrally acting
peripherally acting
Guaifenesin
skeletal muscle relaxant
use in large animal anesthesia
no analgesia or unconsciousness-don’t use as sole agent
what is included in a “triple” drip
GG + alpha 2 agonist + ketamine
dantrolene is used for the Tx of
malignant hyperthermia
what can happen if antibiotics are given IV too quickly
may cause hypotension
when are antihistamines typically given as a premed
before mast cell removal Sx
