Induction Agents and Opioids ☺️ Flashcards
What is the definition of
- analgesia
- anaesthesia
- sedative
- onset
- offset
Analgesia = Pain relief Anaesthesia = unconsciousness Sedative = Anxiolytic Onset = Time taken for drug to start acting Offset = Time taken for drug to stop being effective
Describe the function and properties of GABA
Describe the function and properties of NMDA
GABA
- reduce neuronal activity
- sedative, anxiolytic, anticonvulsant, muscle relaxant
NMDA
-increase neuronal activity => cascade leads to sensitization of DH
Propofol
- positives
- negatives and SE
- metabolism and onset/offset
GABA agonist => IV induction
- antiemetic, itch, convulsant
- BD
- pleasant dreams
- low ICP
- cardiac, resp depression
- no malignant hyperpyrexia risk
SE
- anaphylaxis
- pancreatitis from increased TAG
- thrombophlebitis
Rapid onset and recovery
Metabolised by liver, kidney
Barbiturates vs benzodiazepines
- common properties
- differences
GABA agonists
- anticonvulsants and sedatives
- low ICP
- amnesia
- respiratory depression
- fall in BP, HR
- accumulates in fat
- fast onset, offset
- liver met => kidney excretion
Barbiturates (-pental, -barbital)
- CYP interactions
- v narrow therapeutic index
- NOT ANALGESIC
Benzodiazepines (-am)
- Antidote => flumenazil infusion antidote
- drowsiness, confusion
- paradoxical reactions
Etomidate
- positives
- negatives
- metabolism and excretion
GABA agonist
- NOT ANALGESIC
- low ICP
- no BP, HR fall so can be used in haemodynamic instability
- resp depression
- rapid onset, offset
- liver met => kidney excretion
11b hydroxlyase inhbition => GC, MC adrenal insufficiency
Ketamine
- positives
- negatives
- metabolism and excretion
NMDA antagonist
- analgesic
- sedative
- SNS stimulation, suitable for haemodynamically unstable
- minimal resp depression
- BD
- increased ICP
- liver met => kidney excretion
-nightmares
Morphine
- positives
- negatives
- antidote
MOP agonist, long T1/2
- Liver met => kidney excretion
- analgesia
- N+V
- cough suppression
- resp, cardiac depression
Naloxone infusion due to short T1/2
Fentanyl properties Codeine properties Tramadol properties Remifentanyl properties compared to morphine
Fentanyl - MOP, DOP, short T1/2
- T1/2 increases as infusion time increases
- more potent than morphine
Codeine - MOP, KOP
-less potent than morphine
Tramadol - MOP, SNRI inh
- less potent than morphine
- risk of seretonin syndrome
Remifentanyl - MOP
- vvv short T1/2
- metabolised by blood/tissue esterases (enzymes are everywhere)
- SEDATIVE and ANALGESIA
What is the antidote to opioids
- what are the pharmacokinetics
- what are the SE
Naloxone
-due to short half life, needs infusion
May cause
- rebound agonist
- HTN
- pulmonary edema
- arrythmia
TIVA
- mixture
- pros and cons
Total IV anesthesia
-propofol + remifentanyl
Pros
- no gas
- stable CV
- decreased N+V
- increased tube tolerance
Cons
- based on algorithms
- risk of patient awareness