Opioids and Alpha 2 Agonists Flashcards
how do opioids cause analgesia?
central and peripheral actions
which opioids are more effective analgesics?
agonists> agonist/antagonists or partial agonists
where do alpha 2 agonists enact analgesia?
central and peripheral actions
what is opioid-alpha 2 agonist analgesia synergy?
can use lower doses of each together and get more sedation and analgesia than either drug alone at higher doses
which opioid is used more often for sedation that for analgesia in small animal patients?
butorphanol
which opioid agonists are used in veterinary medicine?
hydromorphone
morphine
fentanyl
methadone
which opioid is a partial agonist?
buprenorphine
what are the most important side effects of opioids?
cardiovascular (bradycardia)
respiratory depression (hypoventilation)
gastrointestinal (nausea, vomiting, constipation)
how do opioids impact cardiac output and MAP?
minimal direct effects
what are thee respiratory effects of opioids?
decreases responsiveness to CO2: hypoventilation
what are the immediate gastrointestinal effects of opioids?
agonists: nausea, vomiting, defecation
what are the long-lasting gastrointestinal effects of opioids?
decrease propulsive motility
what are opioids used for in small animal?
premedication
induction of anesthesia
epidural analgesia
do opioids decrease minimum alveolar concentration (anesthesia) in horses?
not consistently
which opioid is most commonly used in horses?
butorphanol
what happens in camelids and ruminants with opioids?
locomotion: hyperthermia, self injury
gastrointestinal stasis
what is sensitivity to alpha 2 agonists like between species?
huge variations in sensitivity to drug between species
how should you choose an alpha 2 agonist?
intended species on label
duration of effect
route of administration
which systems do alpha 2 agonists have adverse effects in?
cardiovascular
respiratory
gastrointestinal
endocrine
what is hypertension with alpha 2 agonists mediated by?
alpha2B AR
what is the impact of alpha 2 agonists on cardiac output?
dose dependent decrease in cardiac output
overall reduction in organ blood flow
what does using an anticholinergic and alpha 2 agonist cause?
worse hypertension and increases myocardial work
which opioid is a partial agonist?
buprenorphine
what can an IV morphine bolus cause?
histamine release
how do opioids induce bradycardia?
vagally
how do opioids cause hypoventilation?
decrease responsiveness to CO2
do agonist/antagonists or partial agonist opioids cause vomiting?
no
what can be used with opioids in patients with cardio, liver, and renal disease?
benzodiazepine
which patients should you not use opioids in?
head trauma: increases intracranial pressure through hypoventilation
increased risk of aspiration
pneumonia/difficulty sustaining normal oxygenation
cats hyperthermic, dogs hypothermic
what opioid is most commonly used in horses?
butorphanol
which opioid is avoided in horses?
buprenorphine: hard to reverse
what is a significant problem with opioids in camelids?
gastrointestinal stasis
what is the peripheral hypertension with alpha 2 agonists from?
vasoconstriction
how does hypotension occur with alpha 2 agonists?
central effect
alpha2A AR
what is the blood flow reduction from alpha 2 agonists like?
more reduced to skin than vital organs
continues after reversal of drug
do alpha 2 agonists or opioids cause more severe bradycardia?
alpha 2 agonists
what arrhythmias are associated with alpha 2 agonists?
heart block
paroxysmal V tach
what are the respiratory effects of alpha 2 agonists?
decreased
no significant change blood gas
pulmonary edema: ruminants
how do alpha 2 agonists impact mucous membrane color?
similar to dead patient
helps to supplement oxygen
what is kitty magic?
ketamine
butorphanol or buprenorphine
dexmedetomidine
which alpha 2s are used in horses?
xylazine
detomidine
romifidine
how effective are alpha 2 agonists with colic pain in horses?
more effective than opioids or NSAIDs
which ruminants are the most sensitive to alpha 2 agonists?
goats
how sensitive are pigs to alpha 2 agonists?
very resistant to sedative effects
what is important to monitor with alpha 2 agonists?
SPO2
heart rate
blood pressure
blood loss
