Anaesthetic drugs Flashcards
Common IV induction agents
- Propofol
- Sodium thiopentone
- Ketamine
- Etomidate
PESK = induction agents
Propofol - how does it work, what should you know about it
- GABA agonist
- Rapid onset
- Pain on IV injection
- Antiemetic properties
- Rapid metabolism, little accumulated metabolites
- Moderate myocardial depression
- Very common for maintaing sedation on ITU, total IV anaesthesia and daycase
Sodium thiopentone - what to know about it
- Extremely rapid onset - choice for rapid sequence induction
- Marked myocardial depression
- Metabolites build up
- Unsuitable for maintenance infusion
- Little analgesic effects
thiopentONE - fastest ONE
Ketamine - how does it work, what should you know about it
- NMDA receptor antagonist
- Induction
- Moderate to strong analgesia
- Little myocardial depression - good for haemodynamically unstable patients
- Dissassociative anaesthesia can occur - nightmares
Ketamine makes me dream
Etomidate - what to know about it
- Good cardiac safety progile
- No analgesia
- Unsuitable for maintainance - prolonged use can cause adrenal supression
- Post op vomitting = common
TOM made me vomit on the DATE
Inhaled general anaesthetics
- Volatile liquids eg isoflurane, desflurane, sevoflurane
- Nitrous oxide
MOA of volatile liquids
- Unknown really
- May act in combo of GABA A, glycine and NMDA receptors
Adverse effects of volatile liquids
- Myocardial depression
- Malignant hyperthermia
- Halothane - not really used now is hepatotoxic
What are volatile liquids used for?
Induction and maintenance
Nitrous oxide MOA
- Unknown
- May be combination of NMDA, nACh, 5-HT3, GABAa and glycine
Adverse effects nitrous oxide
- May diffuse into gas filled body compartments
- = increase in pressure
- So avoid in certain conditons eg pneumothorax
Use of nitrous oxide
Maintenance and analgesia (eg during labout)
IV general anaesthetics
- Propofol
- Sodium thiopentone
- Etomidate
- Ketamine
MOA of thiopental
- Barbiturate - potentiates GABAa
Adverse effects thiopental
- Laryngospasm
What is important to remember about thiopental?
- Lipid soluble
- Quickly affects brain
Adverse effects of propfol
- Pain on injection - activates pain receptor TRPA1
- Hypotension
Adverse effects Etomidate
- Primary adrenal supression - reversible inhibition of 11b-hydroxylase
Adverse effects of ketamine
- Disorientation
- Hallucinations
Local anaesthetic agents examples
- Lidocaine
- Cocaine
- Bupivacaine
- Prilocaine
How to treat local anaesthetic toxicity?
- IV 20% lipid emulsion
Drug interactions with lidocaine
- Beta blockers
- Ciprofloxacin
- Phenytoin
Features of lidocaine toxicity
- Intial CNS overactivity (blocks inhibitory pathways first)
- Then depression (blocks both)
- Cardiac arrhythmia
When is cocaine used?
- Salt, local anaesthetic is paste form
- Topically on nasal mucosa - vasoconstriction
- Used in ENT surgery
