Mod 1 - Anesthesia Premed 8/16 Flashcards
Quiz 2
what is tranquilization?
behavioral change - relaxed patient but still aware of surroundings
what is sedation?
centrally depressed and drowsy patient that is unaware of surroundings
T/F - if a patient is really wound up, it can override the CNS so that sedation drugs won’t be effective.
True
what is the only phenothiazine drug we use?
acepromazine
what is acepromazine’s MOA and what does this cause? (2)
- blocks dopamine receptors
- antiemetic effect
- loss of thermoregulatory control - blocks alpha-1 receptors
- hypotension
what are some important properties of acepromazine? (6)
- antiemetic
- antihistamine
- antiarrhythmic
- tranquilization
- inc. analgesic efficacy
- dec. MAC
what does MAC stand for?
minimal alveolar concentration
what are 3 side effects of acepromazine?
- platelet aggregation dysfunction (clotting factors affected)
- hypothermia
- hypotension
what are 3 facts of acepromazine’s pharmacokinetics?
- slow onset of action
- long duration of action
- NOT REVERSIBLE
what are 2 other effects you need to keep in mind when using acepromazine?
- dec. Hct by 20-30% (splenic relaxation)
- priapism in horses (prolonged erection w/o stimulation)
T/F - if a patient negatively reacts to acepromazine, you can use a reversal.
False - time and supportive care
T/F - benzodiazepines are reliable sedatives.
False - unreliable!
what are 3 types of benzodiazepines we commonly use?
- diazepam (valium)
- midazolam (versed)
- zolazepam
T/F - there is not a reversal for benzodiazepines.
False - there is one = flumazenil
what are benzodiazepines MOA and what does this cause?
binds to GABA receptors in CNS
- potentiate effects of GABA at receptors - hyperpolarization of neuronal membranes = depression of limbic system, thalamus, hypothalamus
- dec. polysynaptic activity - muscle relaxation
what are 3 properties of benzodiazepines?
- anticonvulsants
- muscle relaxants
- minimum cardiovascular & respiratory depression
T/F - benzodiazepines are a controlled substance.
True
T/F - benzodiazepines work best only in neonates.
False - neonates, geriatric patients, sick patients
T/F - diazepam is NOT water soluble and can ONLY be mixed with ketamine.
True
T/F - midazolam is NOT water soluble and can ONLY be mixed with ketamine.
False - water soluble, multiple administration routes
Diazepam is painful if given 1 and uptake is unpredictable. Diazepam also binds to 2.
- IM
- plastic
what is a side effect of benzodiazepines if given to healthy animals and if it’s the only sedative given in dogs, cats, and horses?
excitation
what is the MOA of alpha-2 adrenergic agonists and what does it cause? (3)
- stimulation of alpha-2 receptors both centrally & peripherally - sedation, analgesia, muscle relaxation
- binds to post-synaptic alpha-2s on sympathetically innervated arterial vessels - vasoconstriction»_space; hypertension
- dec. NE released
what are 5 alpha-2 adrenergic agonists you may see? what patients are they each used in?
- xylazine (SA, LA)
- detomidine (equine, bovine)
- romifidine (equine only)
- medetomidine (mainly zoos/exotics)
- dexmedetomidine (mainly dogs & cats, some horses, zoo/exotics)
what are 3 alpha-2 adrenergic agonist reversals (antagonists)?
- atipamezole
- yohimbine
- tolazoline
alpha-2 adrenergic agonist can cause complex effects on the cardiovascular system. Name 4.
- bradycardia with possible AV block that can cause…
…2. decreased CO - peripheral vasoconstriction that can cause…
…4. hypertension, which turns into hypotension in 45-60min
T/F - we should ALWAYS treat alpha-2 agonist-induced cardiovascular effects with an anticholinergic.
False - bradycardia is VERY patient-specific; what is normal for this patient and this breed?
what are the 3 general properties of alpha-2 agonists?
- great sedation
- good analgesia
- muscle relaxation
T/F - xylazine is the least potent of the 5 alpha-2 agonists, while medetomidine and dexmedetomidine are the most potent (meaning you can use less med/dexmed compared to xylazine).
True
what are 5 side effects that may occur when using alpha-2 agonists?
- emesis (cats)
- dec. GI motility & emptying
- loss of thermoregulation
- hyperglycemia
- diuresis
what is xylazine classified as?
what may occur in sheep with use of xylazine?
alpha-2 agonist
pulmonary edema
what are alpha-2 agonist clinical uses? (3)
- sedation
- diagnostic imaging
- short, minimally invasive procedures
regarding safety, what should you be aware of that may happen when using alpha-2 agonists?
aggression is possible
- dogs bite
- horses bite & kick
what is detomidine?
what species is detomidine used in?
how is it given?
alpha-2 agonist
horses
boluses or CRIs
what is dexmedetomidine?
what species is it used in?
how is it given?
alpha-2 agonist
small animals - mainly for diagnostic imaging
horses - CRI
T/F - we can trust the dosing of dexmedetomidine on Plumbs for small animals.
False - labeled dose is HIGHER than what we clinically use!
what are anticholinergic drugs? (2)
- parasympatholytic
- antimuscarinic
what are the names of 3 parasympatholytic anticholinergic drugs?
- atropine
- glycopyrrolate
- scopolamine
what is the MOA of anticholinergic drugs?
block muscarinic receptors at post-synaptic sites to inc. chronotropy (rate of heart conduction) = inc. HR
- (SA & AV nodes & atrial myocardium get vagal PS input)
- (muscarinic receptors found pre- & post-synaptically at SA & AV nodes)
what occurs to the heart at low doses of anticholinergic drugs?
paradoxical inc. in vagal tone = dec. HR
- once post-synaptic muscarinic blockade occurs, inc. vagal tone resolves & HR inc.
when are anticholinergic drugs indicated? (2)
- +/- bradycardia (it depends)
- hypotension
what are 3 complications that may occur when using anticholinergic drugs?
- inc. O2 consumption
- dec. functional reserve
- other body system side effects
Atropine
- drug type?
- (slow/fast) onset of action
- (short/long) duration of action
- dramatic (dec./inc.) in HR
- (centrally/peripherally) acting
anticholinergic
fast
short
inc.
centrally
glycopyrrolate
- drug type?
- onset of action (slower/faster) than atropine
- (shorter/longer) duration of action than atropine
- not as drastic (dec./inc.) in HR
- (does/does not) cross BBB
anticholinergic
slower
longer
inc.
does not
T/F - anticholinergic drugs are indicated in those patients with glaucoma or those with problems with aqueous humor drainage.
False - CONTRAindicated
when is it indicated to use anticholinergic drugs? (2)
- prevent &/or treat bradycardia & AV blocks
- control muscarinic side effects
T/F - opioid receptors are found throughout the body.
True
what are the 3 types of opioid receptors?
what are properties of each?
- mu - most effective analgesics
- kappa - some analgesia (species dependent), sedation
- delta - some analgesia
Opioids are (hydrophilic/lipophilic). They have extensive metabolism in mammalian species. They are eliminated in 1 & 2.
lipophilic
1. urine
2. feces
When giving opioids, there are fewer side effects seen when given to (healthy/painful) patients due to ?.
painful
upregulation of receptors
what do opioids do?
dec. release of excitatory NTM & hypopolarize nociceptors = dec. transmission within spinal cord
what supraspinal effects do opioids have? (4)
- analgesia
- sedation
- altered thermoregulation
- significant respiratory depression
what can happen if opioids are administered in high doses or via rapid IV infusion?
excitation
Opioids, when combined with other drugs during anesthesia, can cause profound 1 that is characterized by inc. 2.
- respiratory depression
- PaCO2
antitussive effects are produced when opioids bind to 1 & 2 receptors at the cough center in the medulla 3.
- mu
- kappa
- oblongata
when discussing the heart, (bradycardia/tachycardia) commonly occurs with opioid use. This can be reversed via antimuscarinics, such as 1 or 2.
bradycardia
1. atropine
2. glycopyrrolate
opioids can impair coordination of GI 1 and should be used cautiously in 2.
- motility
- horses
which 3 species may develop hypothermia with opioid use?
- dogs
- rabbits
- birds
which 4 species may develop hyperthermia with opioid use?
- cats
- pigs
- goats
- cattle
T/F - schedule 1 drugs have a high potential for abuse with no currently accepted medical use.
True
T/F - schedule 5 drugs have a high potential for abuse with no currently accepted medical use.
False - low abuse potential
maropitant (cerenia) is a very potent 1 and will prevent it by 95%. It is a 2 receptor (ant/agonist) with minimal analgesic properties.
- antiemetic
- NK-1
antagonist
name 4 pure opioid agonists.
- morphine
- methadone
- fentanyl
- hydromorphone
what is an opioid agonist-antagonist?
butorphanol
what is an opioid partial agonist?
buprenorphine
what are 2 opioid antagonists?
which opioid agonist is also considered an antagonist?
- naloxone
- naltrexone
butorphanol
what are 6 side effects of opioids?
- bradycardia
- respiratory depression
- euphoria, dysphoria
- hypothermia
- hyperthermia in cats (w/hydromorphone)
- miosis ()-() (dogs) & mydriasis (0)-(0) (cats)
T/F - fentanyl is 100x more potent than morphine.
True
morphine is an inexpensive pure 1 opioid with an onset of action of 2 and a duration of action of 3.
- mu
- 20-30min
- 2-4hr
T/F - you can use morphine in patients that are going to be skin tested.
False - morphine causes inc. histamine release
T/F - morphine can be used in patients with head trauma, brain tumors, or patients undergoing ophthalmological procedures.
False - causes inc. IOP and may cause vomiting, which will inc. ICP & IOP
hydromorphone has a (shorter/longer) duration of action compared to morphine and is (less/more) expensive.
shorter
more
T/F - hydromorphone is a semisynthetic opioid.
True
T/F - methadone, a synthetic opioid, is the most expensive of the opioids.
True
morphine vs. hydromorphone vs. methadone
- which is the least likely to cause vomiting or histamine release?
- which has mild-moderate NMDA receptor antagonist activity, which is good for chronic or refractory pain?
1 & 2. methadone
hydrocodone is a pure 1 agonist with (poor/excellent) bioavailability in dogs.
what is it used for?
- mu
poor
antitussive
fentanyl is a (short/fast) acting synthetic 1 with _2_x potency compared to morphine. it allows for MAC sparing up to 3%. it lasts 4 after a single IV injection, so it is usually given 5.
- opioid
- 80-100x
- 63%
- 15-30min
- CRI
T/F - buprenorphine has a ceiling effect with variable analgesia.
True
T/F - butorphanol is a great analgesic.
FALSE - great sedative & antitussive, but does NOTHING for pain!
What are 3 common NSAIDs used at MSU that are COX-2 selective (COX-1 sparing)?
- carprofen
- meloxicam
- robenacoxib (onsior)
the duration of action of robenacoxib (onsior) is 1. The label dose for cats is 2.
- 24hrs
- 3d
which is NOT a desired effect of acepromazine?
A. antiemetic
B. MAC reduction
C. priapism
D. anxiolysis
C
T/F - benzodiazepines are reliable sedatives in most small animal patients.
FALSE
which is most likely a side effect shortly after an injection of dexmedatomidine?
A. excitement
B. vomiting
C. tachycardia
D. bradycardia
D.
- profound peripheral vasoconstriction inc. MAP = dec. HR
which scenario is NOT the correct usage of an anticholinergic in most situations?
A. being administered before reversal of paralytic drugs
B. as part of a premed for a healthy & normal patient
C. treating bradycardia & hypotensive patient in surgery
D. preventing bradycardia in a procedure where vagus nerve may be manipulated
B.
