IV anesthetics

Hypnosis, amnesia, analgesia, ms relaxation

• Moderate sedation (still conscious) --> used for not painful procedure
•            -amnesia and analgesia
• Deep sedation (unconscious) --> used for painful procedure
•            -hybrid state (pt placed in moderate sed. (1 min unconscious))

• --Induction agents for inhalational general anesthesia in the OR
• --Adjuncts to inhalational anesthesia
• --Total IV anesthesia (completely unconscious and asleep)
• --IV sedation (breathing on your own, unconscious but arousable)

•Rapid onset (highly lipophillic)

•Rapid redistribution (termination of effects)

• •Often short elimination half-lives -->
• gone quickly

IV: know when the plasma [] peaked. No first pass metabolism

True

false

VRG (kidney, heart, brain and liver) --> Muscle --> Fat

•Single administration - short cases

•Repeated administration or continuous infusion - long cases

• State in which patients are completely
• unconscious and do not respond to surgical stimulus; no sympathetic response to painful stimuli

False

• Conscious
• Maintain their own airway
• could induce amnesia (good)
• not used for painful procedure

a brief period during moderate sedation where pt become unconscious, used for painful procedure.

Propofol because it's easier for patient to wake up from Propofol than Fentenyl during continuous infusion.

•Patient cooperation for venipuncture

• •Rapid onset can magnify overdosage or
• side effects

•Pharmacologic antagonists are available for only some agents (benzodiazepines, opioids)

GABA receptor

Thiopental, MEthohexital and propofol

• cause histamine release
• slow onset

• more potent than thiopental
• short distribution half-life
• short elimination half-life
• may reduce seizure threshold and cause hiccup

• Rapid onset
• Rapid, clear recovery
•            quick initial distribution
•            huge volume of distribution (drop plasma [] quickly --> quick to deliver and eliminate)

• •Respiratory depression (in small dose)
•            apnea

• •Mild direct myocardial depression ( dec
• cardiac contractility)

• •Profound peripheral vasodilation ( given in bolus fashion)
•             Decreased blood pressure ( could invoke reflex tachycardia) but… Propofol also depressed baroreflex response --> Little increase in heart rate
•              (young ppl fine, old people not fine)

• anti-emetic
• painful on injection

• •Formulated in an oil-in-water emulsion containing:
• soybean oil --> cause the burning sensation
• glycerol
• egg lecithin

•Potential allergic reactions

•Potential bacterial growth (soybean oil and egg lecithin) --> need aseptic technique and can’t reuse

•Contributes dietary lipid

•Fatalities in children given prolonged infusions

Antagonist to NMDA receptors (class of glutamate receptor) --> block excitation

• Dissociative anesthetics (body can't communicate with cortex)
•       Analgesia, amnesia, staring into space, horizontal nystagmus
•  
• Used for incorporated pt (induce ms relaxation)

•Lipophillic

• •Rapid onset (30-60 sec after IV injection and 4 min after IM injection)
• 
  •Rapid recovery (distribution half-life 11-16 min & duration of action 10-15 min after IV bolus)

• ---CC stimulation
• THE ONLY DRUG increase heart rate, blood pressure, cardiac output --> inc NE release and block reuptake --> symp surge, but mild direct myocardial depression (masked by NE) --> not given for old pt)

• ---Respiratory maintained
• ---Bronchodilation
• ---no histamine release (good for asthmatic pt)

•Increased secretions

•Airway reflexes intact

•Skeletal muscle hypertonus (not associate with EEG changes)

• •Emergence delirium
• floating feeling, vivid dreams, hallucinations, delirium
• more common in adults than children
• related to dose and rate of administration
• decreased by concomitant benzodiazepines

Ketamine's effect decrease with benzodiazepines

•Minimal cardiovascular change

•Minimal respiratory depression

• rapid onset
• rapid recovery

Wiggle juice --> involuntary myoclonic movement and painful on injection

inhibition of adrenocorticosteroid synthesis --> block stress hormone production

increase nausea and vomiting

• Dose-dependent and cause amnesia
• Small bolus induce minimal risk of respiratory depression
• Big bolus induce unconsciousness and stable CV

Major metabolism by CYP3A4 in liver

Interaction with CYP3A4 inhibitor (erythromycin, cimetidine, grape fruit juice)

• Rapid onset
• Duration of action: 45 min

rapid onset and 45 min duration of action, metabolised by CYP3A4

cause venous irritation and slow metabolism

Selective a2-adrenergic receptor agonist

Use for ADH pt with insomnia --> mainly work in CNS for suppression of sympathetic tone

•Patients are easily arousable despite apparent deep sedative state

hypotension and bradycardia

False

long

Analgesics effect which propofol doesn't have

•Analgesia

•Sedation, euphoria

•Respiratory depression

• •Tolerance (involve down-regulation – need 2 weeks of continuous infusion), physical
• dependence (end up with withdrawal effect – even with beta blocker --> cause rapid HR inc), addiction (psychological state)

•Nausea, vomiting

•Cough suppression

•Chest wall rigidity --> unable to breath

respiratory suppression --> body can't inc ventilation in the presence of inc CO2

•Slow Onset (Peak Effect 15-30 Min. IV)

• •Long Duration (1.5 – 2 hrs)
• Active Metabolite = Morphine-6-Glucuronide
• May Be Useful for Dental Sedation In Long Case

•Mild Histamine Release

•Bradycardia (Vagal Stimulation)

•Inexpensive

•Not very popular

•Synthetic, Resembles Atropine  (anticholinergic )

•HR neutral

• •Pharmacology
• Onset 2 - 4 Minutes IV
• Duration 1 – 2 Hours
• Active Metabolite: Normeperidine

• •Issues:
• Histamine Release (>< asthmatic pt)
• Interaction With MAO Inhibitors
• Inexpensive

•Synthetic - derivative of Meperidine

• •Pharmacology
• Onset ~ 1 Minute
• Highly metabolized by CYP3A4
•     Elimination half-life of 3 to 7 hours
• Duration 20 - 30 Minutes

• •Issues:
• No Histamine Release
• Chest-wall Rigidity
• Inexpensive

more potent than fentanyl

Duration of action 45-60 minutes after single dose

• Used in hospital-setting general anesthesia
• e.g., cardiac anesthesia

1/5 to 1/10th as potent as fentanyl

Shorter duration of action than fentanyl (15-20 minutes)

•2 times as potent as fentanyl

•Shortest duration of action (10 minutes)

•Rapid ester hydrolysis by nonspecific  esterases to inactive metabolites

•Used in TIVA, duration of action similar to propofol

Sulfentanil > Remifentanil > Fentanyl > Alfentanil

Sulfentanyl > Fentanyl > Alfentanyl > Remifentanyl

used 90% of the time

for CV compromised pt (etomidate >midazolam)

TIVA

•Usually Remifentanil or Alfentanil

• Moderate sedation
•         Midazolam = amnesia
•         Fentanyl = analgesia