General Anesthetics Flashcards
(11 cards)
Halothane
inhaled anesthetic
most blood-soluble (inc. size of blood compartment), therefore slowest onset of action
other tissue compartments produce a steeper decline in the concentration gradient from lung to brain, causing delayed onset of anesthesia
hepatotoxicity (halothane hepatitis)
bronchodilating properties
respiratory depressants
desflurane
inhaled anesthetic less blood-soluble partial pressure quickly equilibrates through blood and brain compartments to reach anesthetizing concentrations airway irritation bronchodilating properties respiratory depressants
enflurane
inhaled anesthetic
nephrotoxicity
bronchodilating properties
respiratory depressants
sevoflurane
inhaled anesthetic
nephrotoxicity
bronchodilating properties
respiratory depressants
nitrous oxide
inhaled anesthetic
depress cardiac function in concentration-dependent manner
bronchodilating properties
only inhaled anesthetic that doesn’t cause a dose-dependent decrease in tidal volume and increase in respiratory rate
isoflurane
inhaled anesthetic
airway irritation
bronchodilating properties
respiratory depressants
propofol: MOA, pharmacokinetics
- IV anesthetic
- lipophilic - rapid onset (as are other IV anesthetics)
- most frequently administered drug for induction of anesthesia, also good for maintenance of anesthesia b/c pharmacokinetics allow for continuous infusion
presumed MOA:
potentiation of chloride current mediated through GABA-A receptor complex
pharmacokinetics:
-rapidly metabolized by liver, also extrahepatic metabolism in lungs
- recovery more complete, less “hangover” than thiopental -likely due to high plasma clearance
- termination of drug after single bolus dose = result of redistribution from highly perfused (brain) to less-well-perfused (skeletal muscle) compartments
- context-sensitive half-time is brief, even after prolonged infusion
propofol: effectos
CNS:
- hypnotic, not analgesic
- general suppression of CNS activity
- dec. cerebral blood flow and cerebral metabolic rate (dec. ICP and intraocular pressure)
- dec. cerebral perfusion pressure
Cardiovascular:
-dec. systemic BP (more than other drugs) b/c profound vasodilation in arterial and venous circulation and inhibition of baroreceptor response
Respiratory:
- potent respiratory depressant
- produces apnea after induction dose
- ventilatory response to hypoxia and hypercapnia reduced
other:
- antiemetic activity
- pain on injection is common!
barbiturates: thiopental, methohexital: MOA, pharmacokinetics
- largely been replaced in induction by propofol
- combo of enhancing inhibitory and inhibiting excitatory neurotransmission
pharmacokinetics:
- hepatic metabolism
- thiopental = metabolized more slowly, long elimination half-time
- recovery after single bolus dose= comparable for thiopental and methohexital (depends on redistribution to inactive tissue sites rather than on metabolism)
barbituates: effects
CNS:
- dose-dependent CNS depression (ranging from sedation to general anesthesia when administered as bolus injection
- do not produce analgesia, may reduce pain threshold –> hyperalgesia
- potent cerebral vasoconstrictors, produce decreases in cerebral blood flow, cerebral blood volume, ICP
Cardio:
- dec. systemic BP (b/c peripheral vasodilation)
- minimal inhibition of baroreceptor reflex
Respiratory:
-resp. depressants, typically produce transient apnea
clinical induction of anesthesia, usually occurs in less than 30 sec.
benzodiazapines: midzolam, lorazepam, diazepam
left off here b/c tired -slide 37
