2- Drugs used in premeds Flashcards
3 characteristics a pre-med needs to have
Rapid onset (thus rapidly absorbed)
Centrally acting - distributes to the brain
Relatively short-acting (short elimination time)
When alpha 2 adrenergic receptors are stimulated they release?
Noradrenaline
T/F alpha 2 agonists are associated with marked bradycardia & hypotension
True
List the selectivity from high to low of the follow 3 alpha 2 agonsit
Dexmedetomidine, Xylazine, Medetomidine
Dexmedetomidine (most selective) > Medetomidine >Xylazine (least)
Delta & kappa receptors are 2 of the 4 opioid target receptors. What are the others?
MU & Nociception
What drug class is a dopamine receptor agonist thus causing CNS supression?
Phenothiazine (ACP)
What type of administration of phenothiazines can be erratic and unpredictable?
Oral
What drug class acts is a GABA-A agonist?
Benzodiazepines
Ketamines affect on glutamate
Blocks NMDA receptor - so antagonises the excitatory neurotransmitter glutamate
List the effects of alpha-2 agonists
Marked sedative
muscle relaxant
analgesic properties
How long do alpha-2 agonists take to take effect
rapid onset of action- 5 mins
short duration of action - 40 mins
What drug can antagonise alpha-2 agonists
atipamezole
What drug antagonises opiods
naloxone
What is the half-life of acepromazine
slow elimination
half-life 24-28 hours this means it has a long duration of action
What do benzodiaepines cause
anxiolysis
sedation
hypnosis
NO ANALGESIA
T/F benzodiazepines have high water solubility
False- they have high lipid solubility aiding oral and IM absorption.
Where are benzodiazepines metabolised
liver
Describe the pharmacokinetics of ketamine
Extreme lipid solubility ensures its rapid transfer across BBB
High hepatic clearance- so short half-life
Early regain of consciousness after 15-20 due to re-distribution
