Anesthesiology Exam 2 - Premedications; Phenothiazines, Benzodiazepines

Front 1

etymology of anesthesia?

Back 1

greek = lack of sensation or insensibility

Front 2

anesthesia vs analgesia?

Back 2

anesthesia =/= analgesia

Front 3

what are the phases of general anesthasia?

Back 3

premedication phase, induction phase, maintenance phase: all phases are confluent, not exclusive

Front 4

what is the purpose of pre-medicants?

Back 4

balanced anesthesia, administered before induction of anesthesia with wide variety of functions, components of premedications (drugs may fit in more than one category), neurolept analgesia

Front 5

what is balanced anesthesia?

Back 5

uses of 2 or more drugs that work via different mechanisms so can use smaller amounts of each drug and minimize side effects

Front 6

what are the functions of premeds?

Back 6

(1) provide sedation/tranquilization (2) provide pre-emptive analgesia to prevent central wind-up and allow less total analgesia (3) decrease dose of induction drug which have the smallest therapeutic index of all drugs (4) smooth the induction and recovery (5) decrease need for maintenance drugs (6) provide muscle relaxation since not all induction drugs will do this (7) balance unwanted side effects

Front 7

what are the components of premedication?

Back 7

sedatives/tranquilizers (based on ability to obtund CNS), analgesics (opiods, alpha-2 agonists), anticholinergics

Front 8

what is the difference between tranquilizers and sedatives?

Back 8

no matter how much tranquilizer is given (major = acepromazine, minor = benzodiazepines) never reach unconsciousness while sedatives (alpha-2 agonist) can cause unconsciousness

Front 9

name an example of a major tranquilizer?

Back 9

acepromazine

Front 10

name an example of a minor tranquilizer?

Back 10

benzodiazepines

Front 11

name an example of a sedative?

Back 11

alpha-2 agonist

Front 12

name examples of analgesics?

Back 12

opiods and alpha-2 agonists

Front 13

name examples of anticholinergics?

Back 13

glycopyrrolate and atropine

Front 14

what are categories of sedatives/tranquilizers?

Back 14

phenothiazines (acepromazine; ACP), benzodiazepines (diazepam/midazolam), alpha-2 agonists (xylazine, detomidine, medetomidine, dexmedetomidine)

Front 15

what do we want to know about premed drugs?

Back 15

where the drug works (what receptor, where are they located), desired effect, side effects (CV, respiratory, GI, etc), miscellaneous info (where metabolized, pH, species differences, etc)

Front 16

acepromazine (ACP) and promazine are examples of what?

Back 16

phenothiazines

Front 17

what are examples of phenothiazines?

Back 17

acepromazine and promazine

Front 18

what type of drug is phenothiazine?

Back 18

sedative

Front 19

what are the general features of phenothiazines?

Back 19

major tranquilizer, moderate sedation, most species

Front 20

what are the CNS effects of acepromazine?

Back 20

produces calming and sedation (via anti-dopaminergic (D2) action in the CNS, depresses the reticular activating system (RAS), suppresses sympathetic nervous system (SNS)), may possibly lower the seizure threshold in animals

Front 21

what are the cardiovascular effects of acepromazine?

Back 21

vasodilation (via blockade a-adrenergic receptors in vasculature), anti-arrhythmic (decreases epinephrine induced arrhythmias likely from decrease in SNS), some lines of boxers may have an increases sensitivity

Front 22

what are the respiratory effects of acepromazine?

Back 22

mild respiratory depression, accentuated with other respiratory depressants (eg opiods)

Front 23

what is the anagesic effects of acepromazine?

Back 23

none when used alone, neurolept analgesia (combination of major tranquilizer and opiod) which potentiates the sedation and analgesia of other drugs (ie acepromazine & morphine)

Front 24

what are the pharmacokinetics of acepromazine?

Back 24

long lasting (4-8h), metabolized by liver (extremely long duration of actions, >48h, with liver dysfunction), non-reversible

Front 25

what are the routes of administration of acepromazine?

Back 25

can be administered IV, IM, SQ, can be mixed with other water soluble drugs (ie opiods, glycopyrrolate)

Front 26

what are the miscellaneous effects of acepromazine?

Back 26

anti-emetic (inhibition of dopamine receptors at the chemoreceptor trigger zone), anti-histamine effect, decreases platelet aggregation, alters thermoregulation, paraphimosis (prolapsed penis) in stallions (dose related?, not recommended in breeding stallions)

Front 27

what cautions must be taken with acepromazine?

Back 27

hypotension, CV disease, liver disease, coagulopathy/platelet disease, seizure history/neurologic disease

Front 28

what are examples of butyrophenones?

Back 28

azaperone and droperidol

Front 29

what are azaperone and droperidol examples of?

Back 29

butyrophenones

Front 30

what are the general features of butyrophenones?

Back 30

infrequently used in vet med in USA, azaperone is used in pigs in Canada and Europe, and is calming in wild hoof-stock, droperidol was part of Innovar-Vet (droperidol + fentanyl, an opiod), anti-dopaminergic (D2) (produces calming and sedation, depresses the reticular activating system)

Front 31

what are examples of benzodiazepines?

Back 31

diazepam, midazolam, zolazepam

Front 32

diazepam, midazolam, zolazepam are examples of what?

Back 32

benzodiazepines

Front 33

what are the general features of benzodiazepines?

Back 33

minor tranquilizers, mild sedatives, mild side-effects

Front 34

what are the CNS effects of benzodiazepines?

Back 34

enhancing the inhibitory effects of GABA (produces sedation, anxiolysis), depress the limbic system, thalamus, and hypothalamus, reduce reflex activity resulting in muscle relaxation (spinal cord), mild secation alone (effective in neonates, geriatric or compromised animals: very young, very old, very sick, loss of inhibitions resulting in excited, anxious, and occasionally aggressive behavior, less reliable sedation than ACP or alpha-2agonists), anticonvulsant

Front 35

what are the cardiovascular effects of benzodiazepines?

Back 35

minimal effects to HR, BP, SV, hypotension reported with diazepam (vehicle is propylene glycol)

Front 36

what are the respiratory effects of benzodiazepines?

Back 36

minimal changes to respiratory rate or tidal volume (CO2 minimally changed)

Front 37

what are the analgesic effects of benzodiazepines?

Back 37

no analgesia, possible neurolept activity

Front 38

compare midazolam vs diazepam?

Back 38

diazepam is delivered in 40% propylene glycol, burns with injection, has erratic absorption, hemolysis (hyperosmotic) while midazolam is water soluble, does not burn, can be given IV, IM, SQ

Front 39

how are benzodiazepines metabolized?

Back 39

some metabolites may be active, diazepam in contraindicated with hepatic encephalopathy

Front 40

what is the duration of action for benzodiazepines?

Back 40

short onset of action, short duration of action (species differences, ~20 min following IV injection), can be reversed with flumazenil (benzodiazepine antagonist)

Front 41

what are the miscellaneous effects of benzodiazepines?

Back 41

appetites stimulation in cats possibly due to loss of inhibitions, zolazepam is 1/2 of the mixture of telazol while tiletamine is the other portion

Front 42

what is an example of guaifenesin?

Back 42

glyceryl guaiacolate (GG)

Front 43

what is glyceryl guaiacolate (GG)?

Back 43

guaifenesin

Front 44

what are the general features of guaifenesin?

Back 44

central acting muscle relaxant (depresses nerve impulse transmission brain, brainstem, spinal cord, relaxes both the laryngeal and pharyngeal muscles, mild sedative qualities), relaxation of skeletal muscles (minimal diaphragm effect), excitement-free induction and recovery from anesthesia, potentiates the activity of other CNS depressants, mild decreases in BP and increases in HR.

Front 45

how is guaifenesin administered?

Back 45

perivascular may cause skin sloughing (use IV catheter), causes hemolysis (w/solutions containing >5% GG and/or large volumes, ruminants > than horses)

Front 46

what is the anagesic effects of guaifenesin?

Back 46

none, adjunct to induction agent in horses and ruminants when given just prior to inductions agent of ketamine or thiopental

Front 47

what is a triple drip?

Back 47

GG + ketamine + xylazine, used as a CRI, <1hr anesthesia, general anesthesia

Front 48

which pre-med drug is longest acting?

Back 48

acepromazine

Front 49

which pre-med drug works at the dopamine receptor?

Back 49

acepromazine

Front 50

which pre-med drug is in propylene glycol?

Back 50

diazepam

Front 51

which pre-med drug causes vasodilation?

Back 51

acepromazine

Front 52

what is a neurolept analgesia?

Back 52

a combination of major tranquilizer and opiod (or any sedative ith any opiod); potentiates sedation and analgesia of other drugs

Front 53

what are some examples of neurolept analgesia?

Back 53

(1) ace + hydromorphone/butorphanol (2) detomidine/xylazine + butorphanol (esp horses) (3) medetomidine + hydromorphone