L23 - Anaesthetic Drugs Flashcards
describe an anaesthetic drug
- A reversible drug induced absence of sensation and awareness
describe in the order of depression, which brain areas are affected by anaesthesia
- Cortex
- Midbrain
- Spinal cord
- Medulla
State 3 effects of ethanol
- Medullary depression
- Ataxia
- Sedation
name the 2 main ways in which anaesthesia work (Pharmacodynamics)
1)Stimulation of inhibitory receptors
GABAA
Glycine
2)Inhibition of excitatory receptors
Nicotinic
Serotonin
Glutamate/NMDA
how is GABAa depolarised
influx of chloride ions
causing hyperpolarisation
how is anaesthesia administered
- inhale
- inject
state some inhalation agents
- Oxygen
- Nitrous oxide
- Ideal properties
- Isoflurane
- Other volatile agents
what are the physical properties of inhalational agents
- Cost
- Chemical stability
- Non-flammable/explosive
- Vapourizable
- Environmentally stable
what are the chemical properties of inhalation gases
- Non irritant
Low blood:gas solubility
High potency MAC
Minimal side effects (pharmacodynamics
name some characteristics of IV agents
Rapid and pleasant
Lipid soluble
Redistribution short acting
Metabolised
CVS/RS depression
name an IV agent
- Thiopentone- garlic smell-anti-epileptic
- Propofol
- Ketamine
- Etomidate
- Midazolam
describe the effects of muscle relaxants
Muscle paralysis
Facilitate intubation
Maintain paralysis for surgery/ventilation
how do muscle relaxants work
-work at the NMJ
name an example of a muscle relaxant that is depolarising and describe it
Suxamethonium - Post-synaptic membrane Mimics acetylcholine Rapid onset offset
describe a non-depolarising muscle relaxing agent and give some examples
rocuronium
Competitive with Ach
Ach moiety blocks Na channel with size
Duration is variable
Slower onset
