Pharmacology of anaesthetic agents Flashcards
What makes up the triad of anaesthesia?
- Unconsciousness
- Muscle relaxation
- Analgesia
How are anaesthetic drugs divided?
Inhalational - keep them asleep
Injectable - get them to be asleep
Give some examples of injectable anaesthetic drugs
Propofol
Alfaxalone
Ketamine
Thiopental
Give some examples of inhalational anaesthetic drugs
Isoflurane
Sevoflurane
Halothane
Nitrous oxide
What are the main features of injectable anaesthetics?
- Simple to administer
- Once administered need to metabolise and excrete to get rid of
- Adjustment of doses may be hard
What are the main features of inhalational anaesthetics?
- Special equipment required
- Easy to eliminate from the body
- Easy to adjust depth
- Delivered in oxygen
- Potential for environmental damage
Which neurotransmitter is affected by propofol?
GABA - it is an agonist
What are the effects of Propofol administration at low and high doses?
Low - sedation
High - anaesthesia
How is Propofol administered?
Not lipid soluble so made into an emulsion and given IV
Which injectable anaesthesia drugs is used mostly for equine?
Thiopental
What does MAC stand for?
Minimum alveolar concentration
What is the minimum alveolar concentration of an agent?
When 50% of patients will not respond to a noxious stimulus
How is minimum alveolar concentration given?
As a percentage of atmospheric pressure
Which factors affect the minimum alveolar conc?
Species Age Low oxygen Catecholamines Pregnancy Low blood pressure Body temp
For surgery how many x the MAC do we need?
1.2-1.5
