Lecture #15 - Drugs and Surgery Flashcards
First anesthetics?
Diethyl ether
Diethyl ether was replaced by? in 1956
Halothane, because
General anesthesia induce in patients?
Loss of consciousness/sensation
Amnesia
Relaxation of skeletal musc.
Autonomic and endocrine reflexes are then suppressed
Premedication aims at ?
reduce anxiety, pain, salivation
2 steps of general anesthesia: Induction goal
Second step?
1-Induce unconsciousness very quickly
2-maintains unconsciousness: volatile agent/gases
Inhalation anesthetics all en in?
Barbiturates often end in?
Benzo?
ane
al
am
IV tend to have… structure and volatile agents … structure.
ring - not ring
Pharmakokinetics of Inhalation Anesthesia two major components and their subcompanents?
1-Partial pressure of the gas
2-Blood flow: If high CO, less relative go to brain so reduce induction
If gas dissolved in blood does it still contribute to the gas partial pressure?
No
Is nitrous oxide a gas? Why better then all the other?
No, volatile liquid.
Because it doesn’t decrease blood pressure/respiration
Factors influencing rate of induction (4)?
1-Higher the {} in inspired gas the faster the induction
2-Higher ventilation = faster indution
3-GREATER THE SOLUBILITY OF GAS IN BLOOD, THE SLOWER THE INDUCTION RATE, BECAUSE LESS DRUG ENTERS THE BRAIN AND STAYS IN THE BLOOD.
4-High CO = lower relative {}to brain
MAC?
Minimal Alveolar Concentration = ED50. 1.3MAC is the gold standard
Respiratory depression caused by?
Increasing CO2 level in blood
Inhalationnal have musc. relaxant effect? Does NO have one?
Yes, no.
Metabolization of Inhalationnal?
1-2%, the rest is exhaled. Except halothane 15% met.
Halothane compatible with epinephrine?
NO
Inhalationnal cause vomitting?
Yes by triggering CTZ.
Can NO cause complete general anes.?
No, because would need to be 100%, but you need to give O2 at the same time.
Isoflurane/Sevoflurane sensitize the heart?
No, compatible with EPI
Generally IV have…. cardiovascular/respiratory depressive effects?
less
IV pharmakokinetics?
Lipid soluble, effect is fast with short duration of action
Do IV have a wider margin of safety?
YES
Onset of action of thiopental? Distribution?
30 seconds, distributed throughout the body
Midazolam advantage over diazepam? Danger?
Faster action. Accumulate in the body
Conscious sedation?
Opioid + MIdazolam
Opiod resp. depression caused by?
Inability to respond to higher CO2 blood level
1-“Neurolept” analgesia? and 2-anesthesia?
1-Fentanyl + antipsychotic
2-With NO
Only IV that stimulates Cardio?
Ketamine
Antagonize nausea?
Ondansteron - 5HT blocker
Pharmakodynamics of general anesthetics?
1) Decrease transmitter release at presynaptic terminal
2) Decrease responsivness at post-synaptic
3) Extra-synaptically at pre-synaptic side affecting Ca+ release
4) Extra-synaptically at post-synaptic side affecting tonic inhibition.
Except for ketamine and NO all IV?
Increase GABA inhibition
Ketamine action?
decrease glutamate at NMDA receptor, blocking excitation
Musc. blocking agents (2)?
1- Competitive blocking: Curare derivative, (ium). Compete with acetylcholine
2- Succinylcholine: Activate receptor and keep receptor desensitized.
Succinylcholine danger?
Indi. deficient in pseudocholinesterase, they cannot breakdown the drug. They will stop breathing.
Local analgesia mec. of action?
Act on voltage gated Na+ channel. = stop spreading of action-potential
Local analgesia often given with adrenaline b/c?
Reduce blood flow -> reduce plasma cholinesterase which metabolizes them (also liver meta. them)
Derivative of cocaine, sometime used for?
Cardiac arrythmias
two cat. of local anes.?
Ester and amides (amide = longer half-life)
EMLA?
Eutectic mixture of local anesthetics
