Preanesthetic medications and induction agents Flashcards
What classes of drugs would you use to achieve analgesia?
Anticholinergic?
Neuroleptics?
Analgesia: Opioids, dissociatives, NSAIDs
Anticholinergic: atropine and glycopyrrolate
Neuroleptics: phenothiazines, alpha-2 agonists, benzodiazepines
Opioids are good for what?
Analgesia
mild sedation when used alone
mild CV effects
Decrease the MAC of inhalant
What are the opioid drugs we discussed?
Butorphanol Buprenorphine Hydromorphone Oxymorphone Morphine Methadone Fentanyl
What is the mechanism of action for Butorphanol?
kappa agonist, mu antagonist
Ceiling effect, mild sedation and analgesia
How is butorphanol used in dogs/cats/horses/ruminants
Dogs: alone or with a sedative for non or mildly painful procedures
Horse: with alpha-2 agonist for pre-med
ruminants: During or after induction for large;
Small: with benzo as pre-med
What is the mechanism of action for buprenorphine and what does it do?
Partial mu agonist; little sedation and mild-moderate analgesia
When would you NOT use buprenorphine?
As pre-med for a painful procedure; very sticky for mu receptor and is difficult to reverse
T/F The animal dose for Buprenorphine is very small
TRUE; .01 - .04 mg/kg
What are the full mu agonists?
hydromorphone, morphine, oxymorphone, methadone, and fentanyl
Used for moderate to severe pain
What full mu agonist is also a NMDA antagonist?
Methadone
T/F All of the opioids have a ceiling effect
FALSE; The full mu agonists do not have a ceiling effect
What is unique about the administration of Fentanyl?
It requires an IV catheter and constant rate infusion
When would you use Fentanyl?
As an induction agent in critically ill Small animal patients
What are some sedatives/tranquilizers?
Acepromazine, benzodiazepines, alpha-2 agonists, and dissociatives
What is the reversal agent for Acepromazine?
There is no reversal agent
What effects does Acepromazine have? Any analgesic effects?
More profound/reliable sedation than benzodiazepine; Also significant MAC sparing drug
NO analgesic effects
T/F Acepromazine can cause seizures
FALSE
Dexmedetomidine is classified as a:
alpha-2 agonist
Dexmedetomidine works as a:
Potent sedative and analgesia
Dexmedetomidine should be reserved for use in what kind of patients?
healthy or very painful, fearful, or aggressive patients
What are the reversal agents for Xylazine, Detomidine, and Romifidine/
yohimbine and tolazoline
Diazepam and midazolam are classified as what?
Benzodiazepines
T/F Diazepam and Midazolam are the sedatives of choice for young, healthy dogs and cats
FALSE
What kinds of patients see more profound sedation with Diazepam and Midazolam?
pediatric, geriatric, or critical patients
What effects do Diazepam/Midazolam have?
Muscle relaxants and anticonvulsants; no analgesia
Diazepam contains _____ which makes it painful on injection and toxic at high doses
Propylene glycol
Anti-cholinergic drugs work to do what?
Decrease vagal effects and decrease salivary secretions; Also used to counter vagal effects of anesthetic drugs
Atropine is classified as what?
Anti-cholinergic
T/F Atropine crosses the BBB
TRUE
Glycopyrrolate is classified as what?
Anti-cholinergic
T/F Glycopyrrolate crosses the BBB
FALSE
Glycopyrrolate should be avoided in what animal?
Large animals: cause GI stasis
Guaifenesin is used as what?
Central muscle relaxant
Also in the “triple drip” with ketamine and xylazine
When using Guaifenesin, concentrations should not be above:
5%
Anesthetic induction of dogs and cats:
There’s like 100, look at the powerpoint
Anesthetic induction of horses
ketamine + midazolam +/- GG
Anesthetic induction of ruminants
Triple Drip: GG + xylazine + ketamine
Anesthetic induction of sm. ruminants
ketamine + midazolam OR
ketamine + propofol
Anesthetic induction of camelids
Triple drip OR
ketamine + midazolam
T/F Propofol must be discarded 6 hours after opening
TRUE
What is the mechanism of action for Propofol?
GABA-A receptors
Propofol is used for what?
Sedation, induction, or CRI for maintenance of anesthesia
NO analgesia
What are some precautions for using Propofol?
can cause hypoventilation, potentiates bradycardia, and is cumulative in cats
What is the shelf life of Propofol 28?
28 days dum dum
What is the mechanism of action for ketamine?
NMDA receptor agonist
What is the classification of Ketamine? What is it used for?
Dissociative anesthetic
used to catelepsy, amnesia, and a good analgesia
What are some precautions with Ketamine?
May cause muscle rigidity, may cause seizures, and it is a very rough recovery
What will be different about a patient given Ketamine?
Eyelids will remain open with the pupil centered in the globe
What are some characterists of animals given Telazol
Eyes remain open with globes centered
Maintain palpebral and laryngeal reflexes
Does Telazol provide analgesia?
YES
T/F Cats recover much smoother from Telazol than dogs do
TRUE; Zolazepam lasts longer in the cats
Alfaxalone interacts with what?
GABA A receptors
What is the major advantage and use of Etomidate?
Minimal myocardial depression/hypotension
Anticonvulsant
A dog is presenting with a GDV. What would you use to induce it?
Opioid + Benzodiazepine
Rank the three classes of opioids on their MAC sparing effects
Mu agonists»_space; Buprenorphine»_space; Butorphenol
Opioid analgesics are considered the….
Backbone of analgesic protocals
