Premedication drugs Flashcards
Premedication drug classes (5)
Phenothiazine derivatives
Butyrophenones
Benzodiazepines
Alpha-2-agonists
Opioids
Name 2 classes of tranquilizers
phenothiazines (acepromazine)
butyrophenones (azaperone)
ace causes emesis or nah
powerful antiemetic action in acepromazine
acepromazine effects on respiration and heart rate
little effect on resp. (RR may decrease but minute volume remains unchanged)
HR effects quite minimal and is antiarrhythmic
main side effects of ace
hypothermia
hypotension (vasodilation)
In which breed of dog should you avoid the use of ace?
Some Boxers are highly sensitive to
even small doses of acepromazine given by any route
Vasovagal syncope
Orthostatic hypotension
Bradycardia
side effect of ace in large animals?
ACP causes paralysis of the retractor penis and protrusion of the flaccid penis from the prepuce in bulls and stallions
In stallions physical damage to the
dangling penis may result in swelling and failure of the organ
When used as a premedication in horses, ace reduces
the incidence of death associated with anesthesia and surgery in HORSES
onset of action and time of effect of acepromazine
30-45min given im or sc;
5-6h duration (up to 12h in eq)
azaperone is used as
a sedative and as a preanesthetic medicant in pigs. prevents aggression, used in transport.
is a butyrophenone
Name 5 alfa2 agonists.
Xylazine (Rompun)
Detomidine (Domosedan)
Medetomidine (Domitor)
Dexmedetomidine (Dexdomitor, Cepedex)
Romifidine (Sedivet)
Arrhythmias are common with
xylazine
alfa2agonists may cause what GI changes in ruminants?
Bloat in ruminants and ruminal atony
Hypersalivation
Diarrhea in ruminants after use
Diff between dex- and medetomidine.
Dex- is the left-enantiomer of medetomidine. Same formula, structure but left-mirrored and thus chirality meaning differing properties.
Dex is used at half the dose that med. is used at.
Name 3 alfa2-ANTagonists (reversal agents).
Atipamezole
Tolazoline
Yohimbine
What Antagonizes effects of xylazine in horses
Tolazoline
Describe Morphine
Gold standard opioid
Profound analgesia
Onset time 10 min after IV-administration and 15 min after IM
Administered every 4 hours in dogs and horses and every 6 hours in cats
Vomiting
Describe Methadone (Insistor)
Synthetic full μ-agonist
Very good analgesia
Onset (fast) and duration similar to morphine (4-6h)
Much less likely to induce vomiting
Safe for IV-injection
Describe Fentanyl
Synthetic opioid
Pure μ-agonist
50X more potent than morphine
Rapid onset of action (1 – 2 min)
Short-acting - duration of effect of single dose 20 min
Good for induction protocol in cardiovascularly unstable animal
Describe butorphanol (torphadine)
κ-opioid receptor-agonist/
partial agonist and antagonist activity at the μ-opioid receptor
Sedation provided by agonism of kappa-receptors
Has the ability to reverse the effect of μ-agonists (in case of
respiratory depression)
Safe, high terapeutic index
Minimal cardiovascular and respiratory effects
Good analgesic for cats and ferrets
Provides only mild sedation when used alone
Onset time 5 - 15 min and duration is around 1 hour
describe Buprenorphine
Partial μ-agonist
25 times more potent than morphine
Onset of action is 45 min
Long duration (6 - 8 hours)
Good analgesia
Very effective in chronic pain
Name 3 Opioid Antagonists
Naloxone (emergency)
Naltrexone (longer term)
Diprenorphine (wildlife)
Gamma-aminobutyric acid (GABA) is
the primary physiological inhibitory neurotransmitter in the CNS
Benzodiazepines enhance
the GABA-receptor’s affinity for endogenous GABA (increased effect)
Lack of direct agonist activity leads to a very wide safety margins
