Pharma 8: General Anaesthetics Flashcards
General anesthesia
Definition
Stages
The absence of sensation, which is associated with a reversible loss of consciousness
Stages: Stage 1: Analgesia Stage 2: Excitement Stage 3: Surgical Anesthesia Stage 4: Medullary Paralysis
Thiopental
Type
Barbiturate
Thiopental
MOA
GABA-A modulator—> enhance GABA-A mediated synaptic inhibition
Thiopental
Adv
Fast and potent anesthesia
Thiopental
Disadv
Weak analgesia, muscle relaxation]
Laryngospasm
Cardio, resp depression
Thiopental
Metabolism
Slowly metabolized and accumulates in body fat—> prolonged effect if given repeatedly
Benzodiazepines
Lorazepam
Midazolam
Etomidate
Benzodiazepines
MOA
Enhance GABA-A mediated synaptic inhibition
Common use of Lorazepam and Midazolam
Premedication given ORALLY to reduce anxiety and ease amnesia
Midazolam use
For endoscopy where full anesthesia not required
Entomidate use
IV
An induction agent preferable to Thiopental in pt with circulatory failure and also cuz its metabolized faster
Opioids
Morphine
Fentanyl
Opioids MOA
uReceptor agonists that are used with other anesthetics to cause analgesia
U receptor activation—> inhibit AC—> reduce cAMP—> increase K conductance, decrease Ca conductance—> reduce transmitter release and synaptic transmission
Opioids (morphine, fentanyl) cause
Hypotension
Respiratory depression
Muscle rigidity
Postanesthetic N/V
Opioids as amnesiacs
NOT GOOD
Propofol
Use
Anxiolytic/hypnotic
Induces and maintains anesthesia
Propofol
Recovery, onset
Both rapid
Propofol effect of intracranial pressure
Reduced