Week 2: Pharmacology of Anesthesia Agents Flashcards
What are diagnostic nerve blocks
use example of the lame horse
start with a local anesthetic on the most distal part of the leg and work proximal until you pinpoint area causing lameness
What is the MOA of local anesthetics
Deactivating nerve impulses “numbing the nerve” in a localized area
Where would topical anesthetics typically be used
cornea, larynx, dermatitis and mucus membranes
what are the 4 components of general anesthesia
Hypnosis: sleep
Amnesia: without remembering
Analgesia: No pain
Reflex Suspension and Immobility: muscles relaxed
what is the strategic objective in providing anasthesia without pain
disconnect nocioceptors from perception
What are the four phases of general anesthesia
Pre-induction and anxiolytics
induction
maintenance
recovery
what are some common induction agents
barbiturates
Alpha 2 Agonists
Neuroleptanalgesia
Dissociatives
What is the MOA of barbiturates for induction
displace and block GABA a neurotransmitter
typically with thiobarbiturates (short acting)
What is the MOA of alpha 2 agonists in common induction
what drug is used for this
causes drowsiness, calming, muscle relaxation and some analgesia
Dexmedetomidine (workhorse in A2A)
what is the reversal agent for dexmedetomidine
atipamezole 1:1 reversal dose
define neuroleptanalgesia
combination of opioid and tranquilizer
what are some typical neuroleptanalgesic drug combos
butorphanol + acepromazine + glycopyrollate (BAG)
Dexmedatomidine + Butorphanol + Ketamine (Kitty Magic)
Oxymorphone (CII) + Acepromazine
What is “BAG”
a neuroleptanalgesic for induction
(B) butorphanol + (A) acepromazine + (G) Glycopyrollate
What is the MOA of the induction agent Propofol (Propofol 28)
MOA unknown
has high hypnosis property but low analgesic potency
requires intense monitoring for apnea upon induction
What is the MOA of “Dissociative” for induction agents
disconnecting different pieces of the brain to get analgesia
eye lube: forgeting is MALPRACTICE
what are typical dosage forms for dissociative induction agents
ketamine (CIII)
tiletamine (CIII)
what are some effects of using ketamine by itself
catalepsy causing muscle stiffness and eyes staying open
reason for eye lube
what is the MOA for injectable agent “Muscle relaxants”
blocks connecting neurons between spinal cord and brain stem
what is the MOA of Gas general anesthetics
essentially not understood, but all agents are hydrophilic/lipophilic
probable effects
inhibitory receptors are excited
excitatory receptors are inhibited
What are the common maintenance agents for Gen Anesthesia
Isoflurane
Sevoflurane
What is blood to gas solubility
the ability for an anesthetic to diffuse between alveolar air into the blood
Blood: Gas AKA partition coefficient
What is MAC
Minimum Alveolar Concentration
systemic way to measure strength/potency of inhalant anesthetics
similar to an ED50
What is Sevofluranes “claim to fame”
sweet smell & non irritating
quick acting
