Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Surgery > Anethetics and Analgesics etc. > Flashcards

Anethetics and Analgesics etc. Flashcards

LEARN DAT SH*T

1
Q

Phenothiazines MOA

A
  • Dopamine (D2) receptor blockade within CNS
  • d2 - pre and post-synaptic G-protein coupled receptor
  • blockade leads to decrease in cAMP and adenylate cyclase activity, Ca conductance, and alterations in postsynaptic potassium conductance
  • blockage of alpha 1 adrenergic, muscarinic, and histamine (H1) receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Phenothiazine example

A

Acepromazine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Acepromazine drug type

A

phenothiazine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Phenothiazine negative side effects

A
  • dec stroke volume, CO, arterial blood pressure
  • Dec blood pressure and systemic vascular resistance
  • dec PCV (dt splenic engorgement ofter a1-adrenergic receptor blockade), reduction of platelet aggregation (no impact in clot formation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Acepromazine Effects and duration

A
  • moderate sedation and some muscle relaxation
  • No analgesia
  • some antiemetic and antihistamine effects
  • lasts 4-6 hrs post IM or IV
  • no reversal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Benzodiazepines MOA

A

Enhances the GABA-A receptor’s affinity for GABA resulting in inc chloride conductance and hyperpolarization of postsynaptic cell membranes, preventing propogation of action potentials (GABA is primary inhibitory neurotransmitter in CNS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Benzodiazepines examples

A

midazolam, diazepam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Diazepam specifics

A
  • Benzodiazepine
  • poorly water soluble
  • binds to plastics
  • Metabolized by hepatic microsomal enzymes - do not use with liver dysfunction (results in delayed metabolism/clearance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Benzodiazepines effects

A
  • cause muscle relaxation, some narcosis, amnesia, and no analgesia.
  • anticonvulsant
  • wide thereputid index and overdose is difficult
  • reversal is flumazenil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Benzodiazepines negative side effects

A
  • no significant cardiovascular or respiratory depression

- may cause excitement esp in young animals due to central disinhibitory effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Alpha2-adrenergic receptor agonists - MOA

A
  • Cause a decrease of norepinephrine release in the central nervous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Alpha2-adrenergic receptor agonists - examples

A
  • Xylazine
  • Medetomidine
  • Dexmedetomidine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Alpha2-adrenergic receptor agonists - negative side effects

A
  • Some activity at peripheral alpha1-receptors resulting in vasoconstriction, hypertension, arrhythmogenicity, and paradoxical excitation
  • hypertension can result in reflex bradycardia which can lead to dec sympathetic output and eventually hypotension.
  • hyperglycemia, diuresis, and respiratory depression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Xylazine

A
  • Alpha2:Alpha1 receptor selectivity of 160:1
  • Duration 15-20min after IV or IM
  • induce vomiting in cats
  • associated with 44-fold inc in cardiac arrest during anesthesia in dogs and is not indicated in this species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Alpha2-adrenergic receptor agonists effects

A
  • produce profound sedation, analgesia, and muscle relaxation
  • reversed with atipamazol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Medetomidine

A
  • Alpha2:Alpha1 receptor selectivity of 1600:1
  • Duration of effect 60-90 min
  • causes hypertension and reflex bradycardia in dogs
  • if used alone may result in brief periods of unexpected arousal and aggression, biting nearby personel.
  • increasing dose prolongs duration of effect but does not change the degree of effect
  • bradycardia and hypotension may persist after reversal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Dexmedetomidine

A
  • dextrorotary isomer of the racemic medetomidine

- less sedation and shorter duration of action from medetomidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Opiods MOA

A

Act on G protein-couples receptors to decrease release of neurotransmitters, such as substance P and glutamate, in the presynaptic cell and cause hyperpolarization of the postsynaptic cell.

  • net result is a decrease in neuronal activity and transmission of pain signals
  • Act on any of 3 receptors, µ, κ, and δ located throughout the CNS and peripheral tissues
  • analgesia is primary systemic effects
  • reversed with nalaxone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

µ-receptor

A
  • G protein-coupled receptor

- regulates the majority of clinical effects, including analgesia and side effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

κ-receptor

A
  • G protein-coupled receptor

- plays a role of analgesia but distinguishing that role from that of the µ-receptor is challenging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

δ-receptor

A
  • G protein-coupled receptor

- seems to primarily play a modulating role on the µ-receptor

22
Q

Opioids adverse effects

A
  • ileus and nausea due to increase in segmental contraction and a decrease in propulsive contractions in the small intestine
  • minimal cardiovascular effects except in the case of histamine release (morphine and meperidine) which can cause vasodilation, tachycardia, and hypotension.
  • may cause excitation and dysphoria
  • respiratory depression
23
Q

Morphine

A
  • opioid
  • prototypical opioid with relative potency of 1
  • can cause histamine release, esp in rapid IV administration
  • 3-4hr duration in dogs
  • may cause excitement in cats
  • preservative free morphine is preferred for epidural use as has low lipophilicity. Provides analgesia for 12-24hrs
  • dose dependent incidence of gastroesophageal reflux
24
Q

Hydromorphone

A
  • opioid
  • 8x more potent than morphine at µ-receptor
  • does not cause sig H2 release
  • 2-4hr duration after IV/IM
  • may cause post-op hyperthermia in cats
25
Q

Oxymorphone

A
  • Opioid
  • 10x more potent than morphine
  • does not cause sig H2 release
  • 2-4hr duration after IV/IM/SQ
  • may cause less dysphoria, excitement, and passive gastroesophageal regurgitation than morphine
26
Q

Meperidine

A
  • Opioid
  • 10x more potent than morphine
  • causes significant histamine release
  • 1hr duration after IM
  • Not given IV due to histamine release and subsequent hypotension
  • Can cause serotonin syndrome if given with MAOIs (hyperthermia, anxiety, etc)
  • rarely used in small animals
27
Q

Methadone

A
  • opioid
  • 2x as potent as morphine
  • does not cause histamine release
  • 3-4hr duration
  • also an N-methyl-D-aspartate (NMDA) receptor antagonist that may be associated with fewer excitatory responses in cats vs. other opioids
  • has been administered by epidural injection at the lumbosacral space
28
Q

Fentanyl

A
  • opioid
  • 100x as potent as morphine
  • does not cause histamine release
  • 20-40min duration (given as CRI)
  • more likely to cause bradycardia and apnea than other opioids when given as a rapid intravenous bolus
  • can be administered transdermally via patch or liquid but absorption is variable
  • analogues include remifentanil, sufentanil, and alfentanil
  • chest wall rigidity, “wooden chest,” can occur rarely with fentanyl etc
29
Q

Remifentanil

A
  • opioid
  • unique in that it is metabolized by plasma esterases which produces as extremely short half-life and does not require hepatic or renal metabolism for cessation of effect
30
Q

Buprenorphine

A
  • opioid
  • 40x more potent that morphine at the µ-receptor
  • binds strongly to the µ-receptor but without fully activating that receptor
  • reduced analgesic effect compared with full µ-agonist
  • 4-6 hr duration
  • may reverse some of the analgesia if given after a full µ-agonist
  • does not cause side effects typically associated with a full µ-agonist such as nausea, emesis, histamine release, and respiratory depression.
  • ceiling effect where higher doses are not associated with inc. analgesia or side effects but do result in inc. duration of effect
  • better for avoiding side effects
  • may not provide enough analgesia for more painful conditions
  • tightly binds the µ-receptor and may be difficult to reverse with naloxone
  • Rapidly absorbed TM in cats (much higher volumes/doses rec in dogs)
31
Q

Butorphanol

A
  • Partial µ-receptor antagonist to agonist, κ-receptor agonist
  • does not cause histamine release
  • 30min-2hr duration of effect
  • provides analgesia only sufficient for mild to moderate pain
  • few side effects associated with µ-agonist opioids
  • may be used to partially reverse the effects of full opioid agonists
  • ceiling effect where inc doses do not inc analgesic effect
  • more efficacious antitussive than morphine or codeine
  • Sedation susp to be more profound and prolonged in dogs with MDR1 gene mutation - use lower doses
32
Q

Tramadol

A
  • analogue of codein with weak action at the µ-receptor
  • analgesic effects related to serotonin and adrenergic receptor effects within the CNS
  • Only side effects nausea and ileus
  • primary analgesic effect in humans if d/tmetabolism to O-desmethyltramadol (M1) which acts as a full µ-agonist
  • additional activity of tramadol and M1 as serotonin and NE reuptake inhibitors
  • Well absorbed orally but may not be metabolized well to M1 which may limit analgesic effects
  • better metabolized by cats
  • risk of serotonin syndrome when combines with meperidine, tricyclic antidepressants, or SSRIs.
  • metabolized by the liver and kidneys
33
Q

Hydrocodone

A
  • µ-agonist
  • oral forms
  • oral bioavailability in dogs is poor but is variably metabolized to hydromorphone
34
Q

Codein

A
  • µ-agonist
  • naturally occurring alkaloid structurally similar to morphine
  • poor oral bioavailability in dogs and negligible metabolism to morphine (active metabolite)
35
Q

Naloxone

A
  • pure opioid antagonist that binds competatively to the µ-, κ-, and δ-opioid receptors
  • reverses all opioid
  • duration of action 30-60 min
36
Q

Anticholinergics

A
  • competitively antagonize acetylcholine at postganglionic muscarinic cholinergic receptors in the parasympathetic nervous system
  • minimizes effects of vagal tone, increases heart rate, causes bronchodilaton and reduced airway secretions, mydriasis,
  • includes atropine and glycopyrrolate
37
Q

Atropine

A
  • anticholinergic
  • lipid soluble and crosses the blood brain barrier
  • onset 1min IV, 5min IM
  • duration of action 30min on heart rate
  • can cause transient bradycaria and seccond-degree A-V block (more common with lower doses)
  • causes mydriasis in dogs
38
Q

Glycopyrrolate

A
  • anticholinergic
  • poorly lipid soluble - does not cross BBB
  • 4x potency of atropine
  • Onset in a few min (longer than atropine)
  • cardiovascular effects same as atropine in anesthetized dogs, longer in awake dogs.
  • less likely to cause mydriasis in dogs
39
Q

Doxapram

A
  • analeptic CNS stimulant
  • respiratory stimulant via combo of central and peripheral effects.
  • inc minute vent via inc in RR and tidal volume
  • short duration of action
  • used to stimulate resp in neonates
  • glottal gap wider in larpar dogs prior to injection and small on ins and exp after - reflects paradoxical motion
40
Q

Amantadine and memantine

A
  • dopamine agonist and NMDA receptor antagonist
  • analgesic properties through NMDA antagonism
  • limited use to chronic pain where central sensitization might occur
  • primarily renal excretion
  • CNS stimulation is a side-effect from overdose - use caution in patients receiving other dopamine agonists or SSRIs
41
Q

Gabapentin

A
  • GABA analogues but do not interact with with GABA receptors to produce analgesia
  • MOA not fully understood (dec calcium influx to prevent release of neurotransmitters?)
  • used as an anticonvulsant and for neuropathic and perioperative pain in humans.
  • 30 - 35% of dose undergoes hepatic metabolism while unchanged drug excreted by kidneys
  • Sedation is side effect in dogs - not reported in cats
42
Q

Barbiturates

A
  • Cause depression of the CNS by interfering with passage of impulses to the cerebral cortex
  • categorized via duration of action - in ultrashort actng, maximal effect reached in 30sec
  • includes thiopental and methohexal
  • produce a rapid induction of anesthesia
  • dec cerebral blood flow, cerebral metabolic rate of oxygen, and brain electrical activity - preferred in patients with neurologic disorders
  • metabolized by the liver and renally excreted
43
Q

Thiopental

A
  • barbiturate
  • ultrashort acting
  • 2-5% solutions
  • accidental perivascular administration can cause severe tissue damage in more concentrated solutions
  • repeated injections for maintenance of anesthesia can have cumulative effect and cause prolonged recovery
44
Q

Methohexital

A
  • barbiturate
  • more rapidly metabolized than thiopental
  • effects not cumulative
  • can cause involuntary excitement or emergence delirium if patients not premedicated
45
Q

Dissociative agents

A
  • act via NMDA receptor antagonism. Also act on opioid, monoaminergic, and muscarinic receptors.
  • causes an dissociative anesthetic state caused by interruption of ascending transmission from the unconscious to conscious parts of the brain
  • includes tiletamine (part of Telazol) and ketamine
  • characterized by catalepsy, somatic analgesia, and intact ocular, laryngeal, and pharyngeal reflexes.
  • visceral analgesia is poor
  • less respiratory depression
  • muscle rigidity
  • salivation
46
Q

Ketamine

A
  • dissociative
  • NMDA antagonist
  • causes significant analgesia and anesthesia
  • dec incidence of hyperalgesia and allodynia (windup)
  • use in combo with other analgesics
  • duration of action 15-20min
  • produces mild sympathomimetic effect in patients with an intact sympathetic system
  • Not recommended in patients with heart disease (dec CO)
  • inc intracranial and intraocular pressures
  • does not cause significant resp depression
  • renal excretion - avoid in patients with renal dz
47
Q

tiletamine

A
  • dissociative analgesic
  • sold as Telazol - combo with benzodiazepine zolazepam
  • produces similar effects to ketamine and diazepam
  • only small volumes required for anesthesia
  • telazol duration of action 45-60min
48
Q

Propofol

A
  • GABA receptor agonist - increases inhibition throughout the CNS
  • Also inhibits NMDA receptors- causes sedation/anesthesia, no analgesia
  • Hepatic and extrahepatic metabolism (rapid), cleared by the kidneys
  • rapid induction and clearance - not cumulative
  • hypotension, dec CO, and resp depression, apnea is dose dependent
  • can cause pain on injection and myoclonus
  • ok for neuro dz - dec intracranial and CPP
  • ok for c-section - cleared rapidly from neonate circ
  • IV admin only as bolus or CRI
  • panc???
49
Q

Etomidate

A
  • imidazole derivative
  • GABA agonist - causes hypnosis
  • Causes anesthesia but no analgesia
  • ok for neuro dz - depressed cerebral blood flow and cerebral metabolic o2 rate
  • Little cardio effects
  • can cause apnea
  • causes transient adrenocortical suppression - long term use not rec
  • can cause pain on injection, involuntary mm movements, gagging/retching
50
Q

Alfaxalone

A
  • neuroactive steroid
  • GABA agonist
  • anesthesia/sedation
  • rapid onset and recovery
  • recovery not as good as propofol
  • bolus or CRI
  • IM OR IV
  • hepatic metabolism, renal exretion
  • duration of effect dose dependent
  • ok for neuro dz - cerebral blood flow, met demand, and ICP reduced
  • Cardio depression and apnea

Surgery (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions